GIFT   OF 
MICHAEL  REESE 


CHAPMAN'S 


BLOWPIPE   PRACTICE 


AND 


MINERAL    TABLES. 


3Y  TEE  SAME  AUTHOR. 

AN  OUTLINE  OF  THE  GEOLOGY  OF  CANADA, 

BASED  ON   A  SUBDIVISION   OF  THE  PROVINCES 
INTO   NATURAL  AREAS. 

With  six  Sketch-maps  and  86  figures  of  'characteristic  fossils. 
BY  E.  J.  CHAPMAN,  PH.D.,  LL.D. 

This  work  presents  a  synoptical  view  of  the  geology  of  the  entire  Dominion. 
It  is  used  as  a  book  of  reference  in  University  College,  Toronto  ;  in  Queen's 
College  and  University,  Kingston ;  and  in  the  University  of  Halifax  and 
Science  Department  of  Dalhousie  College,  Nova  Scotia. 

COPP,  CLARK  &  CO,,  1877. 


BLOWPIPE  PRACTICE. 


AN   OUTLINE 


OF 


BLOWPIPE  MANIPULATION  AND  ANALYSIS, 


WITH  ORIGINAL  TABLES, 


FOR  THE 


DETERMINATION  OF  ALL  KNOWN  MINERALS. 


BY 

B.   J.   CHAPMA 

• 
PH.D.,  LL.D. 

PROFESSOR  OF  MINERALOGY  AND  GEOLOGY  IN  UNIVERSITY  COLLEGE  AND 
PRACTICAL 


TORONTO : 

OOPP,    CLARK  &  CO.,   47  FRONT  STREET  EAST. 
1880. 


«'     r     '.,' 


INTRODUCTORY   NOTICE. 


The  title-page  to  this  little  work  indicates  succinctly  the  scope  and 
character  of  the  book.  The  work  comprises  two  distinct  parts  :  an 
introductory  sketch  of  the  use  of  the  Blowpipe  in  qualitative  mineral 
examinations ;  and  a  series  of  Tables,  with  chemical  and  crystallo- 
graphic  notes,  for  the  practical  determination  of  minerals,  generally. 
In  the  first  portion  of  the  work,  the  writer's  aim  has  been  to  sys- 
tematise and  condense  as  far  as  possible :  but,  although  confessedly 
a  mere  outline  of  the  subject,  this  introductory  portion  will  not  be 
found  altogether  devoid  of  original  matter.  The  sixth  section,  more 
especially,  contains  a  new  and  greatly  simplified  plan  of  BLOWPIPE 
ANALYSIS,  by  which  the  general  composition  of  an  unknown  sub- 
stance may  be  determined  in  most  cases  very  rapidly  and  with 
comparatively  little  trouble.  As  a  rule,  the  methods  of  Blowpipe 
Analysis,  hitherto  published,  are  little  more  than  Tables  of  Reac- 
tions. They  attempt  no  separation  of  electro-negative  bodies  from 
bases,  but  mix  up  the  two,  very  illogically ;  and  they  exact  the  per- 
formance of  many  unnecessary  experiments,  by  which  certain  com- 
ponents become  detected  over  and  over  again,  whilst  others  escape 
detection,  altogether,  or  are  recognized  only  after  much  unnecessary 
delay.*  These  defects  are  remedied  very  materially,  it  is  thought, 
in  the  method  now  proposed.  The  Determinative  Tables,  which 
occupy  the  second  and  principal  portion  of  the  work,  are  also  origi- 
nal. In  their  arrangement,  an  attempt  is  made  to  place  bodies  of 
related  composition,  only,  under  the  same  subdivision  :  so  as  to  avoid, 
wherever  possible,  the  unnatural  collocations  so  commonly  seen  in 
Tables  of  this  character.  It  will  be  evident,  however,  that  without 
greatly  increasing  the  number  of  the  Tables,  complete  success  in  this 
respect  is  not  always  attainable.  The  Tables  include,  practically,  all 

*  After  the  first  part  of  this  work  was  in  tjpe  and  entirely  struck  off,  the  author  received 
from  HRRR  LANDAUER,  of  Brunswick,  a  copy  of  his  "  Systematischer  Gang  der  Lothrohr- 
Analyse."  Herr  Landauer's  method  entirely  meets  the  above  objections,  and  is  without  doubt 
the  most  satisfactory  plan  of  Blowpipe  Analysis  hitherto  published.  It  has  been  subsequently 
incorporated  by  its  author  into  a  little  work  on  the  Blowpipe,  an  English  translation  of  which, 
under  the  title  of  "  Blowpipe  Analysis,"  has  recently  appeared. 


o  \ 


VI  BLOWPIPE    PRACTICE. 

known  minerals ;  but  as  many  of  these  are  rarely  met  with,  or  are 
comparatively  of  little  importance,  an  Explanatory  Note,  referring 
only  to  species  of  ordinary  occurrence,  is  attached  to  each  Table.  In 
these  Notes,  more  especially  in  those  which  relate  to  the  concluding 
Tables  of  the  series,  additional  information  is  given  respecting  the 
crystallization,  spectroscopic  reactions,  and  other  distinctive  charac- 
ters of  leading  species.  The  spectroscope  recommended  for  use,  in 
'these  investigations,  is  a  simple,  direct- vision  pocket-spectroscope, 
such  as  can  be  carried  very  conveniently,  with  accompanying  Bun- 
sen-burner  (the  foot  unscrewed),  in  a  spare  corner  of  the  blowpipe 
case. 

SCHOOL  OF  PRACTICAL  SCIENCE,  TORONTO  : 
August  12th,  1880. 


BRIEF  SKETCH  OF  THE  HISTORY  OF  THE  BLOWPIPE. 
The  use  of  the  Blowpipe,  in  the  arts,  dates  from  a  very  distant  period — a 
simple  form  of  the  instrument  having  been  long  employed,  in  the  process  of 
soldering,  by,  jewellers  and  other  workers  in  gold  and  silver.  This  employ- 
ment must  naturally  have  suggested  its  use  to  the  alchemists  ;  and  in  the 
curious  collection  of  woodcuts  known  as  the  Liber  mutus,  in  which  an  alchemist, 
assisted  by  his  wife,  is  depicted  in  the  performance  of  various  chemical  opera- 
tions, the  use  of  the  blowpipe  is  clearly  indicated.  The  Liber  mutus  is  of  very 
uncertain  date,  but  it  belongs,  in  all  probability,  to  the  beginning  of  the  seven- 
teenth century.  The  alchemist  is  here  employed,  it  is  true,  not  in  the  actual 
examination  of  a  substance  by  his  blowpipe,  but  in  the  construction  or  sealing  up 
of  a  glass  vessel.  Nevertheless,  the  use  of  the  instrument  in  the  conversion  of 
calc  spar  into  lime  is  pointed  out  by  ERASMUS  BARTHOLIN  in  his  treatise  on  Ice- 
land Spar,  written  in  1670  j  and  in  the  Ars  vitraria  experimentalis  of  KUNCKEL, 
published  in  1679,  the  blowpipe  is  recommended  for  use  in  the  reduction,  on 
charcoal,  of  metal-holding  bodies,  the  requisite  blast  being  produced  by  a  pair 
of  air-tight  bags.  In  1702,  the  celebrated  alchemist  JOHANN  GEORG  STAHL 
distinctly  refers  to  the  reduction  of  lead  and  antimony,  by  the  fusion  of  what 
are  now  known  as  the  oxides  of  these  metals,  on  a  piece  of  charcoal,  by  means 
of  a  "soldering  pipe"  or  tubulo  ccementorio  aurifabrorum.  JOHANN  ANDREAS 
CRAMER,  in  his  Elements  docimasticce  (1739)  describes  the  use  of  the  instrument 
in  the  examination  of  small  particles  of  metallic  bodies,  and  suggests  the  use 
of  borax  (long  previously  employed  in  soldering,  and  also  by  the  alchemists  in 
crucible  operations)  for  this  purpose.  He  gives  also  a  description  of  a  mouth 
blowpipe  provided  at  its  lower  end  with  a  cylindrical  reservoir  for  the  retention 
of  the  moisture  which  condenses  from  the  operator's  breath. 


INTRODUCTORY    NOTICE.  Vll 

In  Sweden,  a  few  years  later  (1746),  SWEN  RINMAN  published  some  details 
on  the  examination  of  ferruginous  tin-ore,  and  other  minerals,  by  the  blowpipe ; 
and,  in  1748,  ANTON  VON  SWAB — usually,  but  erroneously,  cited  as  the  first 
person  by  whom  the  blowpipe  was  used  in  its  scientific  applications — referred 
to  the  use  of  the  instrument  in  a  paper  on  the  occurrence  of  native  antimony. 
BERGMAN  states  that  VON  SWAB  employed  the  blowpipe  in  1738,  but  the  date 
of  his  first  publication  in  which  reference  is  made  to  its  use  is  ten  years  later,  as 
pointed  out  by  Dr.  HERMANN  KOPP  in  his  valuable  GescMchte  der  Chemie :  1844. 

Up  to  this  time,  however,  no  general  or  systematic  use  of  the  blowpipe 
appears  to  have  been  attempted ;  but  in  1758,  AXEL  FREDERIC  CRONSTEDT, 
who  had  previously  employed  the  blowpipe  in  his  researches  on  nickel  (1751), 
published  anonymously  at  Stockholm  his  celebrated  treatise  on  Mineralogy,  in 
which  a  chemical  classification  of  minerals  was  first  definitely  essayed.  In  this 
work,  the  pyrognostic  characters  of  minerals,  as  determined  by  the  blowpipe, 
are  brought  prominently  into  notice  ;  and  in  addition  to  borax,  the  two  general 
reagents  still  in  use,  bicarbonate  of  soda  ("  sal  sodce  ")  and  microcosmic  salt  or 
phosphor-salt  ("  salfusibile  microcosmicum  ")  are  employed  as  blowpipe  fluxes. 
To  the  English  translation  of  Cronstedt's  work  published  in  1770,  GUSTAV  VON 
ENGESTROM  appended  a  short  but  complete  sketch  of  the  use  of  the  Blowpipe, 
as  then  known  ;  and  JOHN  H  YACINTH  DE  MAGELLAN  added  somewhat  to  this 
sketch  in  the  second  (English)  edition  of  the  work,  published  in  London  in 
1788.  The  plate  which  accompanies  VON  ENGESTROM'S  essay,  exhibits  a 
portable  case  of  blowpipe  apparatus,  comprising,  in  addition  to  the  blowpipe  as 
devised  by  Cronstedt,  a  hammer,  anvil,  magnet,  silver  spoon  and  other  articles 
(but  none,  of  course,  of  platinum),  with  candle,  charcoal,  and  three  small 
bottles  for  fluxes.  This  essay  of  VON  ENGESTROM,  attached  to  his  translation 
of  Cronstedt's  work,  was  translated  into  Swedish  by  RETZIUS  in  1773  ;  and  in 
the  same  year  the  Swedish  chemist  TORBERN  BERGMAN  published  a  memoir 
on  the  blowpipe  reactions  of  lime,  magnesia,  alumina,  and  silica  ;  whilst,  in 
1774,  SCHEELE  described  the  action  of  the  blowpipe  on  manganese  ores, 
molybdenite,  and  other  minerals.  A  few  years  later  (1777)  a  complete  treatise 
in  Latin  on  the  use  of  the  Blowpipe  was  drawn  up  by  Bergman,  and  published, 
soon  after,  under  the  editorship  of  Baron  VON  BORN,  the  metallurgist,  at 
Vienna  (Commentatio  de  tuboferruminatorio,  etc. :  Vindobonce,  1779).  A  Swedish 
translation,  by  HJELM,  was  issued  at  Stockholm  in  1781. 

In  the  preparation  of  this  work,  BERGMAN  was  very  materially  assisted  by 
JOHANN  GOTTLIEB  GAHN.  The  latter  chemist  subsequently  carried  out  an 
extended  series  of  experiments  with  the  blowpipe,  and  discovered  various  new 
methods  of  research.  BERZELIUS,  to  whom  at  an  after  period  he  communicated 
personally  his  mode  of  operating,  states  that  GAHN  always  carried  his  blowpipe 
with  him,  even  on  his  shortest  journeys,  and  submitted  to  its  action  every  new 
or  unknown  substance  that  came  in  his  way.  In  this  manner  he  acquired 
great  skill  in  the  use  of  the  instrument.  He  published  nothing,  however,  on 
the  subject ;  but,  finally,  drew  up  at  the  instigation  of  BERZELIUS  the  short 
sketch  of  the  blowpipe  and  its  applications  contained  in  the  latter's  Larbok 
i  Kemie  first  issued  in  1812.  GAHN  then  undertook,  in  conjunction  with 


Vlll  BLOWPIPE    PRACTICE. 

BERZELIUS,  a  complete  blowpipe  examination  of  all  known  minerals  ;  but  his 
death,  in  1818,  occurred  almost  at  the  commencement  of  this  undertaking. 
BERZELIUS  therefore  carried  on  the  investigation  alone  ;  and  the  results, 
together  with  all  the  improvements  and  new  processes  introduced  by  Gahn 
and  by  himself,  were  published  at  Stockholm  under  the  title  of  Afhandling  om 
Blasrorets  anvandende  i  Chemien,  in  1820.  This  work  has  formed  the  basis  of 
almost  all  that  has  subsequently  been  published  on  the  use  of  the  Blowpipe  in 
qualitative  researches,  althou  gh  many  new  tests  and  methods  of  investigation 
have  been  discovered  since  its  date.  At  the  death  of  its  distinguished  author 
in  1853  it  had  entered  its  fourth  edition,  and  had  been  translated  into  all  the 
leading  European  languages.  An  English  translation  (taken  however  from  a 
French  version)  by  CHILDREN,  appeared  in  1821 ;  and  another  by  Whitney 
(from  the  fourth  German  edition  by  HEINRICH  HOSE)  was  published  at  Boston, 
United  States,  in  1845. 

A  new  era  of  blowpipe  investigation  commenced  in  1827,  when  EDUARD 
HARKORT,  of  Freiberg  in  Saxony,  applied  the  instrument  to  the  assaying  or 
quantitative  examination  of  silver  ores.  HARKORT  left  Germany  for  Mexico, 
and  died  there,  soon  after  the  publication  of  his  essay  on  this  subject  (Probir- 
kunst  mit  dem  Lothrohre,  Freiberg,  1827) ;  but  CARL  FRIEDRICH  PLATTNER, 
to  whom  he  had  shewn  his  method  of  working,  carried  on  this  important 
application  of  the  blowpipe,  and  published  elaborate  memoirs  on  the  assaying, 
by  this  method,  of  gold,  lead,  copper,  tin,  nickel,  and  other  metallic  ores  and 
furnace  products.  His  great  work  on  the  Blowpipe,  bearing  a  similar  title  to 
HARKORT'S  earlier  publication,  appeared  in  1835.  It  reached  a  third  edition 
in  1853 ;  and  since  Plattner's  death  in  1858,  two  other  editions  (the  last 
in  1878)  have  been  issued  under  the  editorship  of  DR.  THEODOR  RICHTER, 
Plattner's  successor  in  the  Freiberg  Mining  Academy.  This  work  has  been 
translated  into  various  languages.  An  American  edition,  by  PROF.  H.  B. 
CORNWALL,  appeared  in  1875. 

Of  late  years,  the  use  of  the  Blowpipe  has  been  greatly  extended  ;  and  nu- 
merous original  memoirs  on  points  relating  to  Blowpipe  Practice  and  Analysis 
have  appeared  from  time  to  time  in  scientific  journals.  But  the  discussion  of 
these  more  modern  investigations  belongs  properly  to  a  future  time.  The 
principal  works  published  since  the  date  of  Plattner's  treatise  are  mentioned 
at  page  21  of  the  present  volume.  To  these  must  be  added  the  Systematic 
Course  of  Analysis  of  J.  LANDAUER,  referred  to  in  the  preceding  note. 


CONTENTS. 


PART  I. 

§  1. — THE  BLOWPIPE  :  ITS  STRUCTURE  AND  GENERAL  USE 1 

§  2.— ACCESSORY  APPLIANCES  AND  REAGENTS 4 

§  3. — STRUCTURAL  PARTS  AND  CHEMICAL  PROPERTIES  OP  FLAME 5 

§  4. — BLOWPIPE  OPERATIONS  : 

I.  The  Fusion  Trial   8 

II.  Treatment  in  closed  Tube  : 

(i)  Treatment  in  Flask  or  Bulb-Tube 9 

(ii)  Treatment  in  Closed  Tube,  proper 10 

III.  Roasting,  and  Treatment  in  Open  Tube : 

(i)  Roasting  on  Charcoal,  Porcelain,  and  other  supports  11 

(ii)  Roasting  and  Sublimation  in  Open  Tubes 11 

IV.  Treatment  with  Nitrate  of  Cobalt 12 

V.  Formation  of  Glasses  on  Platinum  Wire,  or  on  Charcoal : 

(i)  Details  of  Process ;  Flaming,  &c 12 

(ii)  Table  of  Borax  Glasses 12 

(iii)  Phosphor-Salt  Glasses   15 

(iv)  Glasses  formed  with  Carb.  Soda 15 

VI.  Reduction   15 

VII.  Cupellation 18 

VIII.  Fusion  with  Reagents  in  Platinum  Spoon    20 

§  5. — BLOWPIPE  REACTIONS  : 

(i)  Non-metallic  Bodies    22 

1,  Oxygen ;  2,  Hydrogen ;  3,  Sulphur ;  4,  Selenium  ;  5,  Ni- 
trogen ;  6,  Chlorine ;  7,  Bromine ;  8,  Iodine ;  9,  Fluorine ; 
10,  Phosphorus  ;  11,  Boron  ;  12,  Carbon;  13,  Silicon. 

(ii)  Unoxidizable  Metals  30 

14,  Platinum ;  15,  Gold ;  16,  Silver. 

(iii)   Volatilizabk  Metals 32 

17,  Tellurium ;  18,  Antimony ;  19,  Arsenic ;  20,  Osmium  ; 
21,  Mercury ;  22,  Bismuth ;  23,  Lead ;  24,  Thallium ;  25, 
Cadmium ;  26,  Zinc ;  27,  Tin. 


X  CONTENTS. 

§  5. — BLOWPIPE  REACTIONS — (Continued). 

(iv)  Flux-colouring  Metals  40 

28,  Copper;  29,  Nickel;  80,  Cobalt;  31,  Iron;  32,  Tung- 
stenum  ;  33,  Molybdenum  ;  34,  Manganese  ;  35,  Chromium  ; 
37,  Uranium  ;  38,  Cerium  ;  39,  Titanium. 

(v)  Earth  Metals    51 

40,  Tantalum  (?)  ;  41,  Aluminium ;  42,  Glucinum ;  43,  Zir- 
conium ;  44,  Yttrium. 

(vi)  Alkaline-Earth  Metals 54 

45,  Magnesium  ;  46,  Calcium ;  47,  Strontium ;  48,  Barium. 

(vii)  Alkali  Metals    57 

49,  Lithium ;  50,  Sodium ;  51,  Potassium ;  52,  Ammonium. 

§  6. — PLAN  OF  ANALYSIS. 

(i)  Determination  of  the  Chemical  Group  to  which  a  mineral  sub- 
stance belongs    60 

(ii)  Determination  of  the  Base  or  Bases  63 

APPENDIX — ORIGINAL  CONTRIBUTIONS  TO  BLOWPIPE  ANALYSIS. 

1.  Reaction  of  Manganese  Salts  on  Baryta 71 

2.  Detection  of  Baryta  in  the  presence  of  Strontia    71 

3.  Detection  of  Alkalies  in  the  presence  of  Magnesia  72 

4.  Method  of  Distinguishing  the  red  flame  of  Lithium  from  that  of 

Strontium    72 

5.  Method  of  Distinguishing  FeO  from  Fe203  in  Silicates  and  other 

compounds 73 

6.  Detection  of  Lead  in  presence  of  Bismuth 74 

7.  Detection  of  Lithia  in  presence  of  Soda 74 

8.  Action  of  Baryta  on  Titanic  Acid    . . . 75 

9.  Detection  of  Manganese  when  present  in  minute  quantity  in 

mineral  bodies    75 

10.  The  Coal  Assay    76 

11.  Phosphorus  in  Iron  Wire    81 

12.  Detection  of  minute  traces  of  Copper  in  Iron  Pyrites  and  other 

bodies 82 

13.  Detection  of  Antimony  in  tube  sublimates     83 

14.  Blowpipe  reactions  of  Thallium    84 

15.  Opalescence  of  Silicates  in  Phosphor-salt  86 

16.  Reactions  of  Chromium  and  Manganese  with  Carbonate  of  Soda  87 

17.  Detection  of  Cadmium  in  presence  of  Zinc  in  blowpipe  experiments  88 

18.  Solubility  of  Bismuth  Oxide  in  Carbonate  of  Soda  before  the 

blowpipe 88 

19.  Detection  of  Carbonates  in  Blowpipe  Practice 89 

20.  Detection  of  Bromine  in  Blowpipe  Experiments   90 

21.  Blowpipe  reactions  of  Metallic  Alloys     91 


CONTENTS.  XI 

PART  II. 

ORIGINAL  TABLES  FOR  THE  DETERMINATION  OF  MINERALS. 

Introduction  :  Explanation  of  Crystal  Symbols,  &c 95 

Analytical  Index  to  the  Tables 99 

Table  I.,   101;    T.  II.,   103;    T.   III.,   105;    T.   IV.,   110 

(N.B.— Cinnabar  to  be  erased  from  this  Table) ;  T.  V.,  113  ; 

T.  VI.,  115;  T.  VIL,  116;  T.  VIIL,   117;  T.  IX.,  121  ; 

T.   X.,  124;  T.  XL,   130;   T.  XII. ,   132;    T.   XIIL,   135; 

T.  XIV.,  143 ;  T.  XV.,  149 ;  T.  XVI.,  151  ;  T.  XVII.,  163  ; 

T.  XVIIL,  171 ;  T.  XIX.,  174 ;  T.  XX.,  178  ;  T.  XXL,  181  ; 

T.  XXII.,  182 ;  T.  XXIIL,  186  ;  T.  XXIV.,  195  ;  T.  XXV., 

213 ;  T.  XXVI.,  227 ;  T.  XXVIL,  256. 
Index  to  Minerals  described  in  Part  II.  .  .   279 


ADDITIONS   AND   CORRECTIONS. 


PAGE  21. — The  following  works  should  be  added  to  the  list  given  in  the 
foot-note  on  this  page  : — Blowpipe  Analysis  by  J.  LANDAUER  (English  edition), 
1880;  "Clavis  der  Silicate"  by  Dr.  LEOP.  H.  FISCHER,  1864. 

P.  24,  line  8 :— for  "sulphates  "  read  "  most  sulphates."  See  exceptions,  in 
Note  to  Table  XVI.,  page  162. 

P.  28,  bottom  line  :  for  BO3,  read  BJ08. 

P.  33,  line  9: — after  "the  solution  has  a  distinct  reddish-purple  colour," 
add,  "and  imparts  a  dark  stain  to  metallic  silver  or  lead  test-paper,  in  the 
manner  of  a  sulphur  or  selenium  compound." 

P.  58,  line  3  : — erase  the  comma  after  the  word  "  various." 

P.  59,  at  close  of  Potassium  reactions,  add,  "  If  a  piece  of  deep-blue  glass, 
however,  be  held  between  the  spectroscope  and  the  flame,  the  potassium  line 
will  alone  be  visible." 

P.  59,  Foot-note.  In  reference  to  the  statement  in  this  note  it  may  be 
observed  that  the  ash  of  tobacco  shews  the  red  K-line,  in  the  spectroscope,  by 
simple  immersion  in  the  flame,  but  the  Ca-lines  only  appear  when  the  ash  is 
moistened  with  hydrochloric  acid.  If  lithium  be  present  (as  in  the  Periqne 
tobacco,  &c. )  the  crimson  Li-line  also  comes  out  per  se. 

P.  61,  under  "Substances  Indicated"  (Expt.  1),  add,  "(2),  Antimony, 
Tellurium." 

P.  66.  Molybdenum,  placed  under  Group  2  on  this  page,  should  be  placed, 
strictly,  by  itself,  apart— as  yielding  infusible  metallic  grains  and  forming  under 
certain  conditions  a  slight  sublimate.  But  its  true  place  (as  stated  in  the 
text)  is  in  the  Electro-Negative  Table,  and  no  error  is  likely  to  arise  from  the 
arrangement  adopted. 

P.  105.  To  description  of  MARCASITE,  add,  "but  sp.  gr.  slightly  lower, 
viz.,  4 '7-4 *9;"  and  to  description  of  PYRRHOTINE,  add,  "decomposed  by 
hydrochloric  acid,  with  separation  of  sulphur  and  emission  of  sulphuretted 
hydrogen  odour. 

P  110.  Cancel  CINNABAR.  [The  paragraph  relating  to  this  mineral  slipped 
in,  here,  by  some  oversight  during  the  printing  of  the  work.]  See  page  121, 
its  proper  place. 

P.  112,  line  5  from  bottom  :— for  "£K,"  read  "—  £R." 

P.  119,  foot-note  :— for  "HC  acid,"  read  "HC1  acid." 

P.  163,  first  and  second  lines  under  APATITE,  for  "CaO,"  read  "3  CaO." 

P.  164,  line  14  :— for  D  read  C3. 

P.  174: — Erase  the  heading  "A1. — No  WATER  IN  BULB-TUBE;"  or,  other- 
wise, add  "A2. — HYDROUS  SPECIES,"  above  line  8  from  bottom. 

P.  185,  line  10  :— for  130°  33',  read  113°  52'.  The  latter  angle  is  that  of  the 
more  commonly  occurring  pyramid  of  Scheelite,  over  a  middle  edge. 

In  the  Note  to  Table  XIV.,  page  143,  for  Olivine  read  Olivenite. 


AN  OUTLINE 


OP 


BLOWPIPE    PRACTICE, 

AS  APPLIED  TO  THE 

QUALITATIVE  EXAMINATION  OF  MINERAL  BODIES. 


§1. 

THE  BLOWPIPE— ITS  STRUCTURE  AND  GENERAL  USE. 

The  blowpipe,  in  its  simplest  form,  is  merely  a  narrow  tube  of 

brass  or  other  metal,  bent  round  at  one  extremity,  and  terminating, 

«it  that  end,  in  a  point  with  a  very  fine  orifice,  Fig.  1.     If  we  place 

the  pointed  end  of  this  instrument  just  within  the  flame  of  a  lamp, 

common  candle,  or  gas-jet  with  nar- 
row aperture,  and  then  blow  gently 
down  the  tube,  the  flame  will  be 
deflected  to  one  side  in  the  form  of 
a  long  narrow  cone,  and  its  heating 
power    will    be  greatly   increased. 
Many   minerals,  when  held  in  the 
form  of  a  thin  splinter  at  the  point 
of  a  flame  thus  acted  upon,  may  be 
melted  with  the  greatest  ease ;  and 
some  are  either  wholly  or  partially 
volatilized.     Other   minerals,   on   the   contrary,   remain   unaltered. 
Two  or  more  substances,  therefore,  of  similar  appearance,  may  often  be 
separated  and  distinguished  in  a  moment,  by  the  aid  of  the  blowpipe. 
The  blowpipe  (in  its  scientific  use)  has,  strictly,  a  three-fold  appli- 
cation.    It  may  be  employed,  as  just  pointed  out,  to  distinguish 
minerals  from  one  another :  some  of  these  being  fusible,  whilst  others 
are  infusible  j  some  attracting  the  magnet  after  exposure  to  the  blow- 
2 


Fro.  1. 


2  BLOWPIPE   PRACTICE. 

pipe,  whilst  others  do  not  exhibit  that  reaction ;  some  imparting  a 
colour  to  the  flame,  others  volatilizing,  and  so  forth.  Secondly,  the 
blowpipe  may  be  employed  to  ascertain  the  general  composition  of  a 
mineral ;  or  to  prove  the  presence  or  absence,  in  a  given  body,  of  some 
particular  substance,  as  silver,  copper,  lead,  iron,  cobalt,  manganese, 
sulphur,  arsenic,  antimony,  and  the  like.  Thirdly,  it  may  be  used 
to  determine,  in  certain  special  cases,  the  actual  amount  of  a  metallic 
or  other  ingredient  previously  ascertained  to  be  present  in  the  sub- 
stance under  examination. 

In  using  the  blowpipe,  the  mouth  is  filled  with  air,  and  this  is 
forced  gently  but  continuously  down  the  tube  by  the  compression  of 
the  muscles  of  the  cheeks  and  lips,  breathing  being  carried  on  simul- 
taneously by  the  nostrils.  By  a  little  practice,  this  operation  becomes 
exceedingly  easy,  especially  in  ordinary  experiments,  in  which  the 
blast  is  rarely  required  to  be  kept  up  for  more  than  twenty  or  thirty 
seconds  at  a  time.  The  beginner  will  find  it  advisable  to  restrict 
himself  at  first  to  the  production  of  a  steady  continuous  flame,  with- 
out seeking  to  direct  this  on  any  object.  Holding  the  blowpipe  in 
his  right  hand  (with  thumb  and  two  outside  fingers  below,  and  the 
index  and  middle  finger  above  the  tube),  near  the  lower  extremity, 
he  should  let  the  inner  part  of  his  arm,  between  the  wrist  and  the 
elbow,  rest  against  the  edge  of  the  table  at  which  he  operates.  The 
jet  or  point  of  the  blowpipe  is  turned  to  the  left,  and  inserted  either 
into  or  against  the  edge  of  the  flame,  according  to  the  nature  of  the 
operation,  as  explained  below.  After  a  few  trials,  when  sufficient 
skill  to  keep  up  a  steady  flame  has  been  acquired,  the  point  of  the 
flame  may  be  directed  upon  a  small  splinter  of  some  easily  fusible 
material,  such  as  natrolite  or  lepidolite,  held  in  a  pair  of  forceps  with 
platinum  tips.*  Some  little  difficulty  will  probably  be  experienced 
at  first  in  keeping  the  test-fragment  exactly  at  the  flame's  point ;  but 
this,  arising  partly  from  irregular  blowing,  and  partly  from  the 
beginner  feeling  constrained  to  look  at  the  jet  of  the  blowpipe  and 
the  object  simultaneously,  is  easily  overcome  by  half-an-hour's  practice. 
A  small  cutting  of  metallic  tin  or  copper  supported  on  a  piece  of 
well-burnt  soft-wood  charcoal  can  be  examined  in  a  similar  manner. 

*  If  forceps  of  this  kind  cannot  be  procured,  a  pair  of  steel  forceps  with  fine  points,  such  as 
watchmakers  use,  may  serve  as  a  substitute.  It  will  be  advisable  to  twist  some  silk  thread  or 
fine  twine  round  the  lower  part  of  these,  in  order  to  protect  the  fingers.  The  points  must  be 
kept  clean  by  a  file. 


VARIOUS    FORMS    OF    BLOWPIPE. 


In  these  experiments,  the  beginner  must  be  careful  not  to  operate  on 
fragments  of  too  large  a  bulk.  The  smaller  the  object  submitted  to 
the  flame,  the  more  certain  will  be  the  results  of  the  experiment. 

In  out-of-the-way  places,  the  common  form  of  blowpipe  described 
above  is  frequently  the  only  kind  that  can  be  obtained.  It  answers 
well  enough  for  ordinary  operations,  but  the  moisture  which  collects 
in  it,  by  condensation  from  the  vapour  of  the  breath,  is  apt  to  be  blown 
into  the  flame.  This  inconvenience  is  remedied  by  the  form  of  con- 
struction shewn  in  the  annexed  figures,  in  which  the  instrument  con- 
sists of  two  principal  portions,  a  main  stem  closed  at  one  end,  and  a 
short  tube  fitting  into  this,  at  right  angles,  near  the  closed  extremity. 
The  short  tube  is  also  commonly  provided  with  a  separate  jet  or  nozzle 
of  platinum.  In  this  case,  the  jet  can  be  cleaned  by  simple  ignition 
before  the  blowpipe-flame,  or  over  the  flame  of  the  spirit-lamp.  In 


FIG.  2.  FIG.  3.        FIG.  4.  FIG.  5. 

the  variety  of  blowpipe  known  as  "Black's  Blowpipe,"  Fig.  2,  the  main 
tube  is  usually  constructed  of  japanned  tin-plate,  and  the  instrument 
is  thus  sold  at  a  cheap  rate.  Mitscherlich's  Blowpipe,  Fig.  3,  consist* 
of  three  separate  pieces  which  fit  together,  when  not  in  use,  as  shewn 
in  Fig.  4.  This  renders  it  as  portable  as  an  ordinary  pencil-case. 
Fig.  5  represents  Gahn's  or  Berzelius's  Blowpipe,  with  a  trumpet- 
shaped  mouth-piece  of  horn  or  ivory  as  devised  by  Plattner.  This 
mouth-piece  is  placed,  of  course,  on  the  outside  of  the  lips.  It  is 
preferable  to  the  ordinary  mouth-piece,  but  is  not  readily  used  by  the 


4  BLOWPIPE   PRACTICE. 

beginner.     In  length,  the  blowpipe  varies  from  about  severf-and-a-half 
to  nine  inches,  according  to  the  eyesight  of  the  operator. 

§2. 

ACCESSORY  APPLIANCES  AND  REAGENTS. 
In  addition  to  the  blowpipe  itself,  and  the  forceps  described  above, 
a  few  other  instruments  and  appliances  are  required  in  blowpipe 
operations.*  The  principal  of  these  comprise  :  Some  well-burnt,  soft- 
wood charcoal,  and  a  thin  narrow  saw-blade  to  saw  the  charcoal  into 
rectangular  blocks  for  convenient  use ;  a  few  pieces  of  platinum  wire, 
three  or  four  inches  in  length,  of  about  the  thickness  of  thin  twine, 
to  serve  as  a  support  in  fusions  with  borax,  &c.  (see  below) ;  some 
pieces  of  open  glass-tubing  of  narrow  diameter,  and  two  or  three 
small  glass  flasks,  or,  in  default,  a  narrow  test-tube  or  two — the  latter 
used  chiefly  for  the  detection  of  water  in  minerals  (see  below) ;  a 
small  hammer  and  anvil,  or  piece  of  hard  steel,  half-aii-inch  thick, 
polished  on  one  of  its  faces ;  a  triangular  file ;  a  bar  or  horse-shoe 
magnet ;  a  pen-knife  or  small  steel  spatula ;  a  small  agate  pestle  and 
mortar;  a  small  spirit-lamp;  a  platinum  spoon;  a  small  porcelain 
capsule  with  handle ;  and  eight  or  ten  turned  wooden  boxes  or  small 
stoppered  bottles  to  hold  the  blowpipe  reagents.  These  latter  are 
employed  for  the  greater  part  in  the  solid  state,  a  condition  which 
adds  much  to  their  portability,  and  renders  a  small  quantity  sufficient 
for  a  great  number  of  experiments.  The  principal  comprise :  Car- 
bonate of  soda  (abbreviated  into  carb.  soda,  in  the  following  pages), 
used  largely  for  the  reduction  of  metallic  oxides  and  detection  of  sul- 
phides and  sulphates,  manganese,  &c.,  as  explained  below ;  biborate 
of  soda,  or  borax,  used  principally  for  fusions  on  the  platinum  wire, 
many  substances  communicating  peculiar  colours  to  the  glass  thus 
formed ;  and  phosphate  of  soda  and  ammonia,  commonly  known  as 
microcosmic  salt  or  phosphor-salt,  used  for  the  same  purposes  as  borax, 
and  also  for  the  detection  of  silicates  and  chlorides,  as  explained  further 
on.  Reagents  of  less  common  use  comprise :  nitrate  of  cobalt  (in  solu- 
tion); bisulphate  of  potash;  black  oxide  of  copper;  chloride  of  barium; 
metallic  tin ;  bone  ash ;  strips  of  yellow  turmeric  paper,  and  blue  and 
red  litmus  paper ;  with  a  few  other  substances  of  special  employment, 
mentioned  under  §  5,  below. 

*  Only  the  more  necessary  operations,  instruments,  &c.,  are  here  alluded  to. 


THE   BLOWPIPE   FLAME.  7 

copper,  <fec.,  impart  a  crimson,  green,  or  other  colour  to  the  outer  or 
feebly  luminous  cone. 

For  the  production  of  a  reducing  flame  the 
orifice  of  the  blowpipe  must  not  be  too  large. 
The  point  is  held  just  on  the  outside  of  the 
flame,  a  little  above  the  level  of  the  burner 
or  wick,  as  shewn  in  Fig.  8.  The  flame,  in 
its  deflected  state,  then  retains  the  whole  or 
FIG.  8.  a  large  portion  of  its  yellow  cone.  The  sub- 

stance under  treatment  must  be  held  within  this  (although  towards 
its  pointed  extremity),  so  as  to  be  entirely  excluded  from  the  atmos- 
phere ;  whilst,  at  the  same  time,  the  temperature  is  raised  sufficiently 
high  to  promote  reduction.  As  a  general  rule,  bodies  subjected  to  a 
reducing  treatment  should  be  supported  on  charcoal. 

For  ordinary  experiments,  such  as  testing  the  relative  fusibility,  <fec., 
of  minerals,  the  blowpipe  may  be  used  with  the  flame  of  a  common 
candle.  The  wick  of  the  candle  should  be  kept  rather  short  (but  not 
so  as  to  weaken  the  flame),  and  it  should  be  turned  slightly  to  the 
left,  or  away  from  the  point  of  the  blowpipe,  the  stream  of  air  being 
blown  along  its  surface.  A  lamp  flame,  or  that  of  coal  gas,  however, 
gives  a  higher  temperature,  and  is  in  many  respects  preferable.  The 
upper  part  of  the  wick-holder  (or  jet,  if  gas  be  used)  should  be  of  a 
rectangular  or  flattened  oblong  form,  with  its  surface  sloping  towards 
the  left  at  a  slight  angle.*  Either  good  oil,  or,  better,  a  mixture  of 
about  1  part  of  spirit  of  turpentine,  or  benzine,  with  6  parts  of  strong 
alcohol,  may  be  used  with  the  lamp.  If  the  latter  mixture  be  used, 
equal  volumes  of  the  two  ingredients  must  be  first  well  shaken  up 
together,  and  then  the  rest  of  the  alcohol  added.  If  the  wick  crust 
rapidly,  the  turpentine  will  be  in  excess,  in  which  case  another  volume 
of  alcohol  may  be  added  to  the  mixture. 

§4. 

BLOWPIPE  OPERATIONS. 
The  following  are  some  of  the  more  general  operations  required  in 

*  The  most  convenient  flame  for  blowpipe  use  is  that  of  a  small  Bunsen  burner,  into  which  ia 
.dropped  a  narrow  tube  (somewhat  longer  than  the  tube  of  the  burner,  and  with  sloped  and 
flattened  upper  surface),  to  cuj;  off  the  supply  of  air  and  produce  a  luminous  flame.  This  acces- 
sory tube  is  of  course  to  be  removed  when  bulb-tubes  or  solutions  are  heated,  or  when  a  eub- 
c.tance  is  ignited  without  the  aid  of  the  blowpipe. 


8  BLOWPIPE  PRACTICE. 

blowpipe  practice.  The  student  should  master  them  thoroughly,, 
before  attempting  to  employ  the  blowpipe  in  the  examination  or 
analysis  of  minerals.  A  few  additional  operations  of  special  employ- 
ment are  referred  to  in  a  subsequent  section. 

(1)  The  Fusion  Trial. — In  order  to  ascertain  the  relative  fusibility 
of  a  substance,  we  chip  off  a  small  particle,  by  the  hammer  or  cutting 
pliers,  and  expose  it,  either  in  the  platinum-tipped  forceps  or  on  char- 
coal, to  the  point  of  the  blue  flame  (Fig.  7,  above).  If  the  substance 
be  easily  reduced  to  metal,  or  if  it  contain  arsenic,  it  must  be  sup- 
ported on  charcoal  (in  a  small  cavity  made  by  the  knife-point  for  its- 
reception),  as  substances  of  this  kind  attack  platinum.*  In  other 
cases,  a  thin  and  sharply-pointed  splinter  may  be  taken  up  by  the 
forceps,  and  exposed  for  about  half-a-minute  to  the  action  of  the  flame. 
It  ought  not  to  exceed,  in  any  case,  the  size  of  a  small  carraway  seed — 
and  if  smaller  than  this,  so  much  the  better.  If  fusible,  its  point  or 
edge  (or  on  charcoal,  the  entire  mass)  will  become  rounded  into  a  bead 
or  globule  in  the  course  of  ten  or  twenty  seconds.  Difficultly  fusible 
substances  become  vitrified  only  on  the  surface,  or  rounded  on  th& 
extreme  edges ;  whilst  infusible  bodies,  though  often  changing  colour, 
or  exhibiting  other  reactions,  preserve  the  sharpness  of  their  point  and 
edges  intact. 

The  more  characteristic  phenomena  exhibited  by  mineral  bodies- 
when  exposed  to  this  treatment,  are  enumerated  in  the  following 
table :  t 

(a)  The  test-fragment  may  "decrepitate"  or  fly  to  pieces.     Example,  most 
specimens  of  galena.     In  this  case,  a  larger  fragment  must  be  heated  in  a  test- 
tube  over  a  small  spirit-lamp,  and  after  decrepitation  has  taken  place,  one  of 
the  resulting  fragments  can  be  exposed  to  the  blowpipe-flame  as  directed  above. 
Decrepitation  may  sometimes  be  prevented  if  the  operator  expose  the  test- 
fragment  cautiously  and  gradually  to  the  full  action  of  the  flame. 

(b)  The  test-fragment  may  change  colour  (with  or  without  fusing)  and  become 
attractable  by  a  magnet.     Example,  carbonate  of  iron.     This  becomes  first  red, 
then  black,  and  attracts  the  magnet,  but  does  not  fuse.     Iron  pyrites,  on  the 
other  hand,  becomes  black  and  magnetic,  but  fuses  also. 

*  In  order  to  prevent  any  risk  of  injury  to  the  platinum  forceps,  it  is  advisable  (even  if  not 
strictly  necessary  in  all  cases)  to  use  charcoal  as  a  support  for  bodies  of  a  metallic  aspect,  as- 
well  as  for  those  which  exhibit  a  distinctly  coloured  streak  or  high  specific  gravity. 

t  Blowpipe  operations,  as  described  in  this  section,  are  not  intended  to  serve  as  a  course  of 
analysis.  Merely  a  few  examples,  therefore,,  ai»  givea  in.  illustration,  of  their  effects.  For  Plaa, 
of  Analysis,,  see  §  6. 


OPERATIONS.  9 

(cj  The  test-fragment  may  colour  the  flame.  Thus,  most  copper  and  all 
thallium  compounds  impart  a  rich  green  colour  to  the  flame ;  compounds  in 
which  tellurium  or  antimony  is  present,  also  those  containing  baryta,  and 
many  phosphates  and  borates,  with  molybdates  and  the  mineral  molybdenite, 
colour  the  flame  pale  green ;  sulphur,  selenium,  lead,  arsenic,  and  chloride  of 
copper  colour  the  flame  blue  of  different  degrees  of  intensity ;  compounds  con- 
taining strontia  and  lithia  impart  a  crimson  colour  to  the  flame ;  some  lime 
compounds  impart  to  it  a  pale  red  colour;  soda  compounds,  a  deep  yellow 
colour ;  and  potash  compounds,  a  violet  tint. 

(d)  The  test-fragment  may  become  caustic.     Example,  carbonate  of  lime. 
The  carbonic  acid  is  burned  off,  and  caustic  line  remains.     This  restores  the 
blue  colour  of  reddened  litmus  paper. 

(e)  The  test-fragment  may  take  fire  and  burn.     Example,  native  sulphur, 
cinnabar,  common  bituminous  coal,  &c. 

(/)  The  test-fragment  may  be  volatilized  or  dissipated  in  fumes,  either  wholly 
or  partially,  and  with  or  without  an  accompanying  odour.  Thus,  gray  antimony 
ore  volatilizes  with  dense  white  fumes ;  arsenical  pyrites  volatilizes  in  part,  with 
a  strong  odour  of  garlic ;  common  iron  pyrites  yields  an  odour  of  brimstone ; 
and  so  forth.  In  many  cases  the  volatilized  matter  becomes  in  great  part 
deposited  in  an  oxidised  condition  on  the  charcoal.  Antimonial  minerals  form 
a  white  deposit  or  incrustation  of  this  kind.  Zinc  compounds,  a  deposit  which 
is  lemon-yellow  whilst  hot,  and  white  when  cold.  Lead  and  bismuth  are  indi- 
cated by  sulphur-yellow  or  orange-yellow  deposits.  Cadmium  by  a  reddish 
brown  incrustation. 

(g)  The  test-fragment  may  fuse,  either  wholly,  or  only  at  the  point  and  edges, 
and  the  fusion  may  take  place  quietly,  or  with  bubbling,  and  with  or  without  a 
previous  "intumescence  "  or  expansion  of  the  fragment.  Most  of  the  so-called 
zeolites,  for  example  (minerals  abundant  in  trap  rocks),  swell  or  curl  up  on 
exposure  to  the  blowpipe,  and  then  fuse  quietly ;  but  some,  as  prehnite,  melt 
with  more  or  less  bubbling. 

(h)  The  test-fragment  may  remain  unchanged.  Example,  quartz,  and  various 
other  infusible  minerals. 

(2)  Treatment  in  the  Flask  or  Bulb-Tube  (The  Water  Test). — Minerals 
are  frequently  subjected  to  a  kind  of  distillatory  process  by  ignition 
in  small  glass  tubes  closed  at  one  end.  These  tubes  are  of  two  general 
kinds.  One  kind  has  the  form  of  a  small  flask,  and  is  commonly  known 
as  a  "  bulb-tube."  Where  it  cannot  be  procured,  a  small-sized  test- 
tube  may  supply  its  place.  It  is  used  principally  in  testing  minerals 
for  water.  Many  minerals  contain  a  considerable  amount  of  water,  or 
the  elements  of  water,  in  some  unknown  physical  condition.  Gypsum, 
for  example,  yields  nearly  21  per  cent,  of  water.  As  the  presence  of 
this  substance  is  very  easily  ascertained,  the  water  test  is  frequently 
resorted  to,  in  practice,  for  the  formation  of  determinative  groups,  or 


10 


BLOWPIPE    PRACTICE. 


ssparation  of  hydrous  from  anhydrous  minerals.  The  operation  is 
thus  performed.  The  glass  is  first  warmed  gently  over  the  flame  of 
a  small  spirit-lamp  to  ensure  the  absence  of  moisture,  and  is  then  set 
aside  for  a  few  moments  to  cool.  This  effected,  a  piece  of  the  sub- 
stance under  examination,  of  about  the  size  of  a  small  pea,  is  placed 
in  it,  and  ignited  over  the  spirit-lamp — as 
shewn  in  the  annexed  figure — the  tube 
being  held  in  a  slightly  inclined  position. 
If  water  be  present  in  the  mineral,  a  thin 
film,  condensing  rapidly  into  little  drops, 
will  be  deposited  on  the  neck  or  upper  part 
of  the  tube.  As  soon  as  the  moisture 
begins  to  shew  itself,  the  tube  must  be 
brought  into  a  more  or  less  horizontal 
position,  otherwise  a  fracture  may  be 
occasioned  by  the  water  flowing  down  and 
coming  in  contact  with  the  hot  part  of  the 
glass.  The  neutral,  acid,  or  alkaline  con- 
dition of  the  water,  can  be  determined  by  slips  of  blue  and  red  litmus 
paper.  A  mineral  may  also  be  examined  for  water,  though  less  con- 
veniently, by  ignition  before  the  blowpipe-flame  in  a  piece  of  open 

tubing,  as  shewn  in  Fig. 
1 0.  To  prevent  the  tube 
softening  or  melting,  a 
strip  of  platinum  foil  may 
be  folded  around  it  where 
the  test-fragment  rests. 
Fl°-  10-  The  latter  is  pushed  into 

its  place  by  a  thin  iron  wire.     The  moisture  condenses  011  each  side 
of  the  test-matter. 

(3)  Treatment  in  Closed  Tubes,  proper. — In  addition  to  the  flask  or 
bulb-tube,  small  pieces  of  narrow  glass  tubing — closed,  and  sometimes 
drawn  out  to  a  point,  at  one  extremity — are  frequently  used  in  the 
examination  of  mineral  bodies.  The  substance  is  ignited  (either  alone, 
or  mixed  with  thoroughly  dry  carb.  soda  or  other  flux)  at  the  closed 
end  of  the  tube.  After  the  insertion  of  the  test-substance,  the  upper 
part  of  the  tube  must  be  cleaned  by  a  piece  of  soft  paper  twisted  round 
an  iron  wire,  or  by  the  feather  end  of  a  quill  pen,  &c. ;  but  this  will 
not  be  necessary  if  the  substance  be  inserted  by  means  of  a  narrow 


OPERATIONS.  13 

plunged  into  the  flux,  the  adhering  portion  of  the  latter  being  then 
fused  into  a  glass.  If  a  sufficient  portion  to  fill  the  loop  be  not  taken 
up  at  first,  the  process  must  be  repeated.  With  beginners,  the  fused 
glass  is  often  brownish  or  discoloured  by  smoke,  but  it  may  be  rendered 
clear  and  transparent  by  being  kept  in  ignition  for  a  few  moments  before 
the  extreme  point  of  the  flame,  the  carbonaceous  matter  becoming 
oxidized  and  expelled  by  this  treatment.  When  carbonate  of  soda  is 
used,  a  small  portion  of  the  flux  must  be  moistened  and  kneaded  in 
the  palm  of  the  left  hand,  by  a  knife-point  or  a  small  spatula,  into  a 
slightly  cohering  paste,  which  is  placed  on  the  loop  of  the  wire,  and 
fused  into  a  bead.  Whilst  hot,  the  soda  bead  is  transparent,  but  it 
becomes  opaque  on  cooling.  The  portion  of  test-matter  added  to  a 
glass  or  bead,  formed  by  these  reagents,  must  be  exceedingly  small, 
otherwise  the  glass  may  become  so  deeply  coloured  as  to  appear  quite 
black.  In  this  case,  the  colour  may  be  observed  by  pinching  the  bead 
flat  between  a  pair  of  forceps,  before  it  has  time  to  cool.  It  is  always 
advisable,  however,  in  the  first  instance,  to  take  up  merely  a  minute 
particle  or  two  of  the  test-substance,  and  then  to  add  more  if  no  char- 
acteristic reaction  be  obtained.  The  glass,  in  all  cases,  must  be  examined 
first  before  an  oxidating  flame,  and  its  colour  observed  both  whilst 
the  flux  is  hot  and  when  it  has  become  cold  ;  and,  secondly,  it  must 
be  kept  for  a  somewhat  longer  interval  in  a  good  reducing  flame 
(Fig.  8),  and  its  appearance  noted  as  before.*  With  certain  sub- 
stances (lime,  magnesia,  &c.)  the  borax  and  phosphor-salt  glasses 
become  milky  and  opaque  when  saturated,  or  when  subjected  to  the 
intermittent  action  of  the  flame  —  the  latter  being  urged  upon  them 
in  short  puffs,  or  the  glass  being  moved  slowly  in  and  out  of  the 
flame  —  a  process  technically  known  as  Flaming. 

The  colours,  &c.,  communicated  to  these  glasses  by  the  more  com- 
monly occurring  constituent  bodies,  are  shewn  in  the  annexed  tabular 
view. 

BORAX. 


Violet  or  amethystine  ........  Ma.gane.e  .  .  .  .  j  *%£%  * 

Violet-brown  (whilst  hot)  .  .  )  XT-  i    i  r\  j 

Clear-brown  (when  cold).  .  .  .  |  Nlckel  ..........  <***?  and 

Blue  (very  intense)  ..........  Cobalt  ..........  Blue  (very  deep). 

*  The  colour  of  the  glass  ought  not,  of  course,  to  be  examined  by  the  trantmitted  light  of  the 
lamp  or  candle  flame.    Strictly,  it  should  be  observed  by  daylight. 


14 


BLOWPIPE   PRACTICE. 


Colour  of  Bead  after  exposure 
to  an  Oxidating  Flame. 

Green  (whilst  hot)    

Blue  or  greenish-blue  (cold) . . 

Green  or  bluish-green 

Green  (dark) 

Yellowish  or  reddish  (hot) . . 
Yellowish-green  (when  cold). 

Yellow  (whilst  hot) 

Greenish-yellow  (cold) , 

Yellowish  or  reddish    

Yellowish  or  reddish    

Enamelled  by  flaming 

Yellow  (whilst  hot) 

Pale  yellowish  (cold)    

Enamelled  by  flaming 

Yellow  (hot) 

Colourless  (cold)    

Enamelled  by  flaming 

Yellow  (hot) 

Colourless  (cold)    

Enamelled  by  flaming 

Yellow  (hot) 

Colourless  or  yellowish  (cold) 
Grayish  and  opaque  byflaming 


Compounds  of: 


Colour  of  Bead  after  exposure 
to  a  Reducing  Flame. 

SMore  or  less  colourless  whilst 
hot ;  brownish-red  &  opaque 
on  cooling. 

Cobalt  +  Iron  ....  Green  or  bluish-green. 
Copper-f  Nickel  )  Brownish-red,    opaque,    on 
Copper+Iron. .  \    cooling. 

Chromium Emerald-green. 

Vanadium  . ,  . .  j  i^^y^^^'cdd), 

Iron Bottle-green. 

Uranium Green  (black  by  flaming). 


Cerium    . 
Titanium. 


Tungstenum 


>  Molybdenum 


Yellow  or  yellowish -red  (hot) 

Yellowish  or  colourless,  and 

'  often  opaline,  when  cold . . 

Yellowish  (hot) 

Colourless  (cold)    

Opaque- white  when  saturated 


Colourless(permanentlyclear) 

Slowly  dissolved   

tfeeunder  Phosphor-salt,below 


r  Lead    

J  Bismuth  ... 

1  Silver 

I  Antimony   . . 


Cadmium    . 


)  Aluminium. 

V  Silicon 

Tin 


Colourless.  When  saturated, 
opaque-white  on  cooling  or 
by  flaming 


r  Tantalum    . . 

Zirconium   . . 

Glucinum    . . 

Yttrium,  &c. 

Thorium .... 

Magnesium.  . 

Calcium  .... 

Strontium  . . 

Barium    .... 

Lithium  .... 

Natrium  .... 
I  Kalium    .... 


(  Colourless  or  yellowish. 
(  Opaque-white,  if  saturated. 

Yellow  or  yellowish -brown. 
Enamelled  light-blue  by  flam* 


See  under  Phosp.  -salt,  below. 
(  Yellow  or  yellowish-brown. 
<  Enamelled  by  flaming. 
(  £eeunderPhosphor-salt,below 
f  Brown  or  gray,  semi-opaque, 
j    often  with  separation  of  black 
I    specks. 

I  Seeunder  Phosphor-salt,below 
(  Gray  and  opaque  on  cooling ; 
but  after  continued  subjec- 
tion to  the  flame,  the  glass 
becomes  clear :  the  reduced 
metallic  particles  either  col- 
lecting together  or  Volatil- 
izing. 

Colourless  —  the    reduced 
metal  being  volatilized. 

Colourless:  permanently 
clear.  (Tin  compounds  dis* 
solve  in  small  quantity  only. 
On  charcoal,  they  become 
reduced  to  metal,  especially 
if  a  little  carb.  soda  be  added 
I  to  the  glass). 


Colourless.  When  saturated, 
opaque-white  on  cooling  or 
by  flaming. 

See  REACTIONS,  §  5. 


OPERATIONS. 

PHOSPHOR-SALT.  *  [> 

The  glasses  produced  by  the  fusion  of  constituent  bodies  with  this 
are  for  the  greater  part  identical  with  those  obtained  by  the  use  of 
although  somewhat  less  deeply  coloured  as  a  general  rule.  The  princii 
exceptions  are  the  glasses  formed  in  a  reducing  flame  with  compounds  of 
molybdenum,  tungstenum,  and  titanium,  respectively.  The  molybfteajiiff  * 
glass  presents,  when  cold,  a  fine  green  colour,  and  the  tungstenum  glass 
becomes  greenish-blue.  If  the  latter  contain  iron,  the  colour  of  the  glass  ia 
changed  to  blood-red  or  brownish-red.  Titanium  in  the  presence  of  iron  gives 
a  similar  reaction ;  but  when  free  from  iron,  the  glass  is  yellow  whilst  hot,  and 
violet- coloured  when  cold.  Phosphor-salt  is  an  important  reagent  for  the 
detection  of  silica  in  silicates,  as  the  silica  remains  for  the  greater  part  undis- 
aolved  in  the  glass,  in  the  form  of  a  translucent  flocculent  mass,  technically 
known  as  a  "silica  skeleton,"  the  associated  constituents  being  gradually 
taken  up  by  the  flux.  A  small  amount  of  silica  is  also  generally  dissolved, 
but  this  is  precipitated  as  the  bead  cools,  rendering  it  semi-transparent  or 
opaline.  Phosphor-salt  is  likewise  employed  for  the  detection  of  chlorides,  &c. 
(See.  under  REACTIONS,  §  5. )  In  other  respects,  it  is  especially  adapted  for  fusions 
on  charcoal,  as  it  does  not  spread  out  like  borax,  but  forms  a  globule  on  the 
support. 

CARBONATE  OF  SODA. 

This  reagent  is  principally  used  to  promote  the  reduction  of  oxidized  and 
other  bodies  to  the  metallic  state,  as  explained  below,  under  that  process. 
It  is  also  of  very  frequent  employment  as  a  test  for  sulphur  in  sulphides  and 
oxidized  bodies.  (See  under  REACTIONS,  §  5.)  It  is  rarely  used,  on  the  other 
hand,  for  the  formation  of  glasses  on  platinum  wire,  except  as  a  test  for  the 
presence  of  manganese  ;  although,  when  employed  in  this  manner,  it  serves  to 
distinguish  salts  of  the  alkalies,  and  tho^  of  strontia  and  baryta,  from  all 
other  salts  :  the  alkalies,  with  baryta  and  strontia,  dissolving  completely  and 
rapidly  in  the  bead,  whereas  lime,  magnesia,  alumina,  and  other  bases,  remain 
unattacked.  Manganese  compounds  form  by  oxidizing  fusion  with  this  reagent 
a  green  glass,  which  becomes  blue  or  bluish-green  and  opaque  on  cooling.  A 
very  minute  amount  of  manganese  may  be  thus  detected.  The  delicacy  of  the 
test  is  increased  by  the  addition  of  a  small  quantity  of  nitre,  as  this  promotes 
oxidation  ;  and  if  the  substance  contain  much  lime,  magnesia,  iron  oxides,  or 
other  bodies  more  or  less  insoluble  in  carb.  soda,  it  is  advisable  to  add  a  little 
borax  to  the  test-mixture.  The  blue  or  bluish-green  bead  thus  produced,  is 
technically  known  as  a  "turquoise  enamel."  Chromium  compounds  produce 
a  somewhat  similar  reaction ;  but  if  the  bead  be  saturated  with  silica  or  boracic 
acid,  it  will  remain  green  in  the  latter  case  ;  while  if  the  green  colour  result 
from  the  presence  of  manganese,  a  violet  or  amethystine  glass  will  be  obtained. 
Some  other  applications  of  carbonate  of  soda  as  a  blowpipe  reagent  will  be 
found  under  the  head  of  REACTIONS,  §  5. 

(8)  Reduction. — This  term  denotes  the  process  by  which  an  oxidized 
or  other  compound  is  converted  into  the  metallic  state.  Some  com- 


16  BLOWPIPE  PRACTICE. 

pounds  become  reduced  by  simple  ignition  •  others  require  for  their 
reduction  the  addition  of  certain  reagents ;  and  some,  again,  resist 
reduction  altogether.  The  reduced  metal  is  in  some  cases  so  highly 
volatile  that  it  cannot  be  obtained  except  by  a  kind  of  distillatory 
process.  In  other  cases,  one  or  more  fusible  globules,  or  a  number 
of  minute  infusible  grains,  are  obtained  in  blowpipe  operations. 
Reducible  metals  may  be  thus  distributed  into  three  groups,  as  shewn 
(with  omission  of  a  few  metals  of  rare  occurrence)  in  the  annexed 
table: 

A.  Yielding    metallic    globules. — Gold,    silver,    copper,  tin,    lead,    bismuth* 

antimony. 

B.  Yielding  infusible  metallic  grains. — Platinum,  iron,  nickel,  cobalt,  molyb* 

denum,  tungstenum. 

C.  Yielding  metallic  vapours  only,  when  treated  on  charcoal. — Mercury,  arsenic, 

cadmium,  zinc. 

A  metal  of  the  first  group  may  be  obtained,  unless  present  in  very 
small  quantity,  by  a  simple  fusion  of  the  previously  roasted  test-sub- 
stance, with  some  carbonate  of  soda,  on  charcoal,  in  a  good  reducing 
flame  (Fig.  8,  above).  In  ordinary  cases,  metallic  globules  are  rapidly 
produced  by  this  treatment.  By  a  little  management  the  globules 
may  be  brought  together,  so  as  to  form  a  single  large  globule.  This 
must  be  tested  on  the  anvil  as  regards  its  relative  malleability,*  <fec. 
Gold,  silver,  copper,  tin  and  lead  are  malleable ;  bismuth  and  anti- 
mony, more  or  less  brittle.  Gold  and  silver  (if  pure)  retain  a  bright 
surface  after  subjection  to  an  oxidating  flame.  Copper  becomes 
covered  with  a  black  film,  and  tin  with  a  white  crust.  Lead  and 
bismuth  volatilize  more  or  less  readily,  and  deposit  on  the  charcoal 
a  yellow  coating  of  oxide.  Antimony  is  rapidly  volatilized  with  de- 
position of  a  dense  white  incrustation  on  the  charcoal.  It  is  not,  of 
course,  always  necessary  to  subject  the  test-substance  to  a  previous 
roasting  (Operation  4,  above),  but  it  is  always  safer  to  do  so.  Sul- 
phur in  most,  and  arsenic  in  all  cases,  must  be  driven  off  by  this 
preliminary  treatment  before  the  actual  process  of  reduction  is 
attempted. 

When  the  metal  to  be  reduced  belongs  to  the  second  group,  or  if 

*To  test  the  relative  malleability  of  a  metallic  globule  as  obtained  by  the  blowpipe,  the 
globule  must  be  placed  on  a  small  steel  anvil,  and  a  strip  of  thin  paper  (held  down  by  the  fore* 
finger  and  thumb  of  the  left  hand)  being  placed  over  it  to  prevent  dispersion,  it  is  struck  once 
or  twice  by  a  light  hammer.  Thus  treated,  malleable  globules  become  flattened  into  discs, 
whilst  brittle  globules  break  into  powder 


OPERATIONS.  17 

the  amount  of  a  fusible  metal  in  the  test- substance  be  less  than  4  or 
5  per  cent.,  the  operation  is  performed  as  follows :  A  small  portion 
of  the  substance  in  powder — subjected  previously  to  the  roasting  pro- 
cess, if  it  contain  sulphur  or  arsenic — is  mixed  with  3  or  4  volumes 
of  carbonate  of  soda  (or  neutral  oxalate  of  potash,  or  a  mixture  of 
about  equal  parts  of  carb.  soda  and  cyanide  of  potassium — -the  latter, 
it  must  be  remembered,  a  highly  poisonous  substance),  and  the  mix- 
ture is  exposed  on  charcoal  to  a  good  reducing  flame,  until  all  the 
alkaline  salt  has  become  absorbed.  More  flux  is  then  added,  and 
the  operation  is  repeated  until  the  whole  or  the  greater  part  of  the 
test-matter  is  also  absorbed.  This  effected,  the  charcoal,  where  the 
assay  rested,  is  removed  by  a  sharp  knife-point,  and  carefully  ground 
to  powder  in  a  small  agate  mortar  or  porcelain  capsule,  whilst  a  fine 
stream  of  water  is  projected  upon  it  from  time  to  time,  until  all  the 
carbonaceous  and  other  non-metallic  particles  are  gradually  washed 
away.  For  this  purpose,  the  mortar  or  capsule  may  be  placed  in  the 
centre  of  an  ordinary  plate ;  and  if  the  operator  be  not  provided  with 
a  chemical  washing-bottle,  he  may  use  a  small  syringe,  or,  in  place  of 
this,  a  simple  piece  of  glass  tubing,  five  or  six  inches  in  length  and 
about  the  fourth  of  an  inch  in  diameter,  drawn  out  at  one  end  to  a 
point.  This  is  filled  by  suction,  and  the  water  is  expelled,  with  the 
necessary  force,  by  blowing  down  the  tube.  The  metallic  grains  or 
spangles  obtained  by  this  process  must  be  examined  by  the  magnet. 
Those  of  iron,  nickel  and  cobalt  are  magnetic.  Sometimes,  however,, 
when  but  a  trace  or  very  small  percentage  of  reducible  metal  is  con- 
tained in  the  test-substance,  its  presence  is  only  indicated  by  a  few 
metallic  streaks  on  the  sides  and  bottom  of  the  mortar.  Metallic 
markings  of  this  kind  can  be  removed  by  a  piece  of  pumice. 

Metallic  compounds  referable  to  the  third  group,  yield  no  metal  on 
charcoal,  or  by  other  treatment  in  open  contact  with  the  atmosphere. 
The  presence  of  arsenic,  however,  is  easily  made  known  by  the  garlic- 
like  odour  evolved  during  fusion  with  reducing  agents  (or  alone)  on 
charcoal.  Cadmium  and  zinc  may  also  be  recognized  by  the  oxidized 
sublimates  which  they  deposit  on  the  charcoal.  The  cadmium  sub- 
limate is  reddish-brown ;  the  zinc  sublimate,  lemon-yellow  and  phos- 
phorescent whilst  hot,  and  white  when  cold.  Mercury  forms  no 
incrustation  on  charcoal ;  but  its  presence  in  any  compound  may  be 
determined  by  reduction  with  carbonate  of  soda  or  iron-filings  in  a 
3 


18  BLOWPIPE    PRACTICE. 

glass  tube  of  narrow  diameter.  A  small  test-tube  or  piece  of  glass 
tubing  closed  at  one  end  before  the  blowpipe,  may  be  used  for  the 
experiment.  The  test-substance,  in  powder,  mixed  with  3  or  4  vols. 
of  perfectly  dry  carb.  soda,  is  inserted  into  the  tube  by  means  of  a 
narrow  strip  of  glazed  writing-paper  bent  into  the  form  of  a  trough , 
so  as  to  prevent  the  sides  of  the  glass  from  being  soiled,  and  the 
mixture  is  strongly  ignited  by  the  spirit-lamp  or  by  the  blowpipe- 
flame.  If  mercury  be  present,  a  gray  metallic  sublimate  will  be 
formed  near  the  upper  part  of  the  tube.  By  friction  with  an  iron 
wire,  or  the  narrow  end  of  a  quill -pen,  &c.,  the  sublimate  may  be 
brought  into  the  form  of  fluid  globules,  which  can  be  poured  out  of 
the  tube,  and  are  then  easily  recognized  as  metallic  mercury. 

(9)  Cupellation. — Gold  and  silver  are  separated  by  this  process  from 
other  metals.  The  test-metal  is  fused  wdth  several  times  its  weight 
of  pure  lead.  The  button,  thus  obtained,  is  exposed  to  an  oxidating 
fusion  on  a  porous  support  of  bone  ash,  known  as  a  cupel.  The  lead 
and  other  so-called  base  metals  become  oxidized  by  this  treatment,  and 
•are  partly  volatilized,  and  partly  absorbed  by  the  bone  ash,  a  globule 
of  gold  or  silver  (or  the  two  combined)  being  finally  left  on  the  sur- 
face of  the  cupel.  For  blowpipe  operations,  cupels  are  generally 
made  by  pressing  a  small  quantity  of  dry  bone  ash  into  a  circular 
iron  mould,  the  latter  being  fixed,  when  presented  to  the  flame,  in  a 
special  support,  consisting  essentially  of  a  wooden  foot  and  pillar 
supporting  a  wire  stem,  with  three  or  four  short  cross-wires  at  the 
top,  between  which  the  cupel-mould  rests.  Instruments  of  this  kind 
cannot  be  obtained  in  remote  places,  but  the  process  may  be  performed 
equally  well  by  pressing  some  dry  bone  ash  into  a  suitable  cavity 
fashioned  at  the  extremity  of  a  cylindrical  piece  of  pumice  or  well- 
baked  clay,  or  even  charcoal.  The  smooth  end  of  the  agate  pestle, 
or  a  glass  button  cemented  to  a  cork,  or  the  rounded  end  of  a  glass 
stopper,  may  be  used  for  this  purpose.  The  cupel,  thus  formed,  must 
then  be  exposed  for  a  few  moments  to  the  point  of  the  blowpipe-flame^ 
so  as  to  render  the  bone  ash  perfectly  dry ;  and  if  its  surface  become 
blistered  or  be  in  any  way  affected  by  this  drying  process,  it  must  be 
rendered  smooth  again  by  pressure  with  the  pestle.  The  substance 
to  be  cupelled  must  be  in  the  metallic  state ;  if  not  in  this  condition, 
therefore,  it  must  first  be  subjected  to  the  reducing  operation  described 
above.  The  piece  of  test-metal,  which  may  weigh  about  a  couple  of 


OPERATIONS.  19 

grains  (or  from  100  to  150  milligrammes)  is  wrapped  in  a  piece  of 
pure  lead-foil  of  at  least  four  times  its  weight,  and  the  whole  is 
exposed,  on  the  surface  of  the  cupel,  to  the  extreme  point  of  a  clear 
oxidating  flame.  If  the  substance  consist  of  argentiferous  lead,  as 
obtained  from  galena,  &c.,  the  addition  of  the  lead-foil  is  of  course 
unnecessary,*  As  soon  as  fusion  takes  place,  the  cupel  must  be 
moved  somewhat  farther  from  the  flame,  so  as  to  allow  merely  the 
outer  envelope  of  the  latter,  or  the  warm  air  which  surrounds  this, 
to  play  over  the  surface  of  the  globule.  By  this  treatment,  the  lead 
will  become  gradually  converted  into  a  fusible  and  crystalline  slag. 
When  this  collects  in  large  quantity,  the  position  of  the  cupel  must 
be  slightly  altered,  so  as  to  cause  the  globule  to  flow  towards  its  edge, 
the  surface  of  the  lead  being  thus  kept  free  for  continued  oxidation. 
When  the  globule  becomes  reduced  to  about  a  fourth  or  fifth  of  its 
original  bulk,  the  process  is  discontinued,  and  the  cupel  is  set  aside  to 
cool.  This  is  the  first  or  concentration  stage  of  the  process.  Another 
cupel  is  then  prepared  and  dried ;  and  the  concentrated  globule — after 
careful  separation  from  the  slag  in  which  it  is  imbedded — is  placed 
on  this  new  cupel,  and  again  subjected  to  the  oxidizing  influence  of 
the  flame.  During  this  second  part  of  the  process,  the  flame  is  made 
rather  to  play  on  the  surface  of  the  cupel  around  the  lead  button  than 
on  the  button  itself,  a  complete  absorption  of  the  oxidized  lead  being 
thus  effected.  The  flame  should  be  sharp  and  finely-pointed,  and 
urged  down  on  the  cupel  at  an  angle  of  forty  or  forty-five  degrees. 
Finally,  if  the  test-metal  contain  gold  or  silver,  a  sudden  flash  or 
gleam  will  be  emitted  at  the  close  of  the  operation,  and  a  minute 
globule  of  one  (or  both)  of  these  metals  will  be  left  on  the  surface  of 
the  bone  ash.  By  concentrating  several  portions  of  a  test  substance, 
melting  the  concentrated  globules  together,  again  concentrating,  and 
finally  completing  the  cupellation,  as  small  an  amount  as  half  an  ounce 

*  In  reducing  galena,  with  a  view  to  test  the  lead  for  silver  by  cupellation,  the  reduction 
may  be  conveniently  performed  as  follows  :  A  small  portion  of  the  galena,  crushed  to  powder, 
is  mixed  with  about  twice  its  volume  of  carb.  soda,  to  which  a  little  borax  has  been  added. 
This  is  made  into  a  paste  by  the  moistened  knife-blade,  and  a  short  piece  of  thin  iron  wire  is 
stuck  through  it,  and  the  whole  is  then  placed  in  a  charcoal  cavity,  and  exposed  for  a  couple 
of  minutes  to  the  action  of  a  reducing  flame.  By  a  little  management,  the  minute  globules  of 
lead  which  first  result  can  easily  be  made  to  run  into  a  single  globule.  The  iron  serves  to  take 
up  the  sulphur  from  the  galena.  When  the  fused  mass  is  sufficiently  cool,  it  is  cut  out  by  a 
sharp  knife-point,  and  flattened  (under  a  strip  of  paper)  on  the  anvil.  The  disc  of  reduced 
lead,  thus  separated,  is  then  ready  for  cupellation.  See  also,  under  silver,  §  5. 


20  BLOWPIPE   PRACTICE. 

of  gold  or  silver  in  a  ton  of  ore — or  in  round  numbers,  about  one 
part  in  sixty  thousand — may  be  readily  detected  by  the  blowpipe.* 

During  cupellation,  the  process  sometimes  becomes  suddenly  arrested. 
This  may  arise  from  the  temperature  being  too  low,  in  which  case  the 
point  of  the  blue  flame  must  be  brought  for  an  instant  on  the  surface 
of  the  globule,  until  complete  fusion  again  ensue.  Or,  the  hindrance 
may  arise  from  the  bone  ash  becoming  saturated,  when  a  fresh  cupel 
must  be  taken.  Or,  it  may  be  occasioned,  especially  if  much  copper  or 
nickel  be  present,  by  an  insufficient  quantity  of  lead.  In  this  latter 
case,  a  piece  of  pure  lead  must  be  placed  in  contact  with  the  globule, 
and  the  two  fused  together ;  the  cupel  being  then  moved  backward 
from  the  flame,  and  the  oxidating  process  again  established. 

(10)  Fusion  with  Reagents  in  Platinum  Spoon. — This  operation 
is  only  required  in  certain  special  cases,  as  in  the  examination  of  a 
substance  suspected  to  be  a  tungstate  or  molybdate,  or  in  searching 
for  the  presence  of  titanic  acid,  &c.  The  substance,  in  fine  powder, 
is  mixed  with  three  or  four  parts  of  the  reagent  (carb.  soda,  or  bisul- 
phate  of  potash,  &c.),  and  the  mixture,  in  successive  portions,  is  fused 
in  a  small  platinum  spoon.  As  a  rule,  the  flame  may  be  made  to 
impinge  upon  the  bottom  of  the  spoon ;  and  the  operation  is  termi- 
nated when  bubbles  cease  to  be  given  off  and  the  mixture  enters  into 


FIG.  12. 

quiet  fusion.  During  the  operation  the  spoon  is  held  in  the  spring- 
forceps  (Fig.  12),  the  points  of  which  remain  in  close  contact  when 
the  sides  are  not  subjected  to  pressure.  The  fusion  accomplished,  the 

spoon  is  dropped,  bottom  upwards,  into 
a  small  porcelain  capsule  (Fig.  13)  pro- 
vided with  a  handle.  Some  distilled 
water  is  then  added  and  brought  to  the 
boiling  point  over  the  spirit-lamp.  The 
Fl°-  13-  fused  mass  quickly  separates  from  the 

spoon,  and  it  can  then  be  crushed  to  powder  and  again  warmed  until 

*  A  cupellation  bead  may  appear  from  its  pure  white  colour  to  consist  of  silver  only,  and 
may  yet  contain  a  notable  amount  of  gold.  A  white  bead,  therefore,  should  be  flattened  into 
a  disc,  and  fused  with  some  bisulphate  of  potash  in  a  small  platinum  spoon.  By  this  treatment 
the  silver  is  removed  from  the  surface  of  the  disc,  and  the  latter,  if  gold  be  present,  assumes  a 
yellow  colour.  If  the  metal  be  again  fused  into  a  globule,  the  white  colour  is  restored. 


REACTIONS.  21 

solution,  or  partial  solution,  takes  place.  When  the  undissolved  mat- 
ters have  settled,  the  clear  supernatant  liquid  is  decanted  carefully 
into  another  capsule  (or  into  a  test-tube)  for  further  treatment.  (See 
Experiments  7  and  8,  in  §  6,  beyond.) 

§5. 

BLOWPIPE  REACTIONS. 

In  this  section,  the  leading  reactions  of  the  more  important 
elementary  bodies  and  chemical  groups  are  passed  rapidly  under 
review.  Bodies  of  exceptional  occurrence  as  mineral  components — 
or  such  of  these,  at  least,  as  cannot  be  properly  detected  by  the  blow- 
pipe— are  omitted  from  consideration.*  The  other  elementary  sub- 
stances are  taken  in  the  order  shewn  in  the  following  index  : 

I.  Non-metallic  Bodies.— I,  Oxygen;  2,  Hydrogen;  3,   Sulphur; 
4,  Selenium ;  5,  Nitrogen ;  6,  Chlorine ;  7,  Bromine ;  8,  Iodine ;  9, 
Fluorine;  10,  Phosphorus;  11,  Boron;  12,  Carbon;  13,  Silicon. 

II.  Unoxidizable  Metals. — 14,  Platinum;  15,  Gold;  16,  Silver. 

III.  Volatilizable  Metals. — 17,   Tellurium;    18,   Antimony;    19, 
Arsenic ;  20,  Osmium ;  21,  Mercury ;  22,  Bismuth ;  23,  Lead ;  24, 
Thallium;  25,  Cadmium;  26,  Zinc;  27,  Tin. 

IV.  Flux-colouring  Metals.— 2%,  Copper;  29,  Nickel;  30,  Cobalt; 
31,  Iron:  32,  Tungstenum ;  33,  Molybdenum;  34,  Manganese;  35, 
Chromium;  36,  Vanadium;  37,  Uranium;  38,  Cerium;  39,  Titanium. 

V.  "Earth"   Metals. — (40,   Tantalum?);    41,   Aluminium;    42, 
Glucinum ;  43,  Zirconium ;  44,  Yttrium. 

*  For  full  details  respecting  the  blowpipe  reactions  of  inorganic  bodies  generally,  the  following 
works  may  be  especially  consulted:  1.  The  old  work  by  Berzelius,  "Die  Anwendung  des 
Lothrohrs,"  etc. ;  translation  of  the  4th  edition,  by  J.  D.  Whitney :  Boston,  1845.  2.  "  Hand- 
buch  der  Analytischen  Chemie,"  von  Heinrich  Rose,  6th  edition,  by  R.  Finkener :  Leipsig, 
1871.  3.  Plattner's  "  Probirkunst  mit  dem  Lothrobr,"  5th  edition,  by  Richter,  1878.  American 
translation  of  4th  edition,  by  H.  B.  Cornwall :  New  York,  1875.  4.  "  Untersuchungen  mit  dem 
Lothrohr,"  by  Dr.  H.  Hartmann  :  Leipsig,  1862.  5.  "  Lothrohr-Tabellen,"  by  Dr.  J.  Hirsch- 
wald :  Leipsig  und  Heidelberg,  1875.  6,  "Manual  of  Determinative  Mineralogy  and  Blowpipe 
Analysis,"  by  George  J.  Brush  :  2nd  edition,  1878.  7.  "  Leitfaden  bei  qual.  und  quan.  Loth- 
rohr-Untersuchuagen,"  von  Bruno  Kerl,  2nd  edition,  Clausthal,  1877.  For  the  determination 
of  minerals,  &c.,  the  far-renowned  "  Tabellen"  of  Von  Kobell  (in  addition  to  the  work  of  Prof. 
Brush,  essentially  constructed  on  that  of  Von  Kobell,  although  with  much  amplification  and 
addition  of  new  matter)  may  be  especially  consulted.  The  "  Anleituiig  zum  Bestimmen  der 
Mineralien,"  of  Dr.  Fuchs,  is  also  a  very  serviceable  little  book ;  and  some  useful  tables  will 
be  found  at  the  end  of  E>  S,  Dana's  excellent  "Text  Book  of  Mineralogy." 


BLOWPIPE   PRACTICE. 

VI.  Alkaline-Earth  Metals. — 45,  Magnesium ;  46,  Calcium :  47, 
Strontium;  48,  Barium. 

VII.  Alkali  Metals.— 49,  Lithium;   50,  Sodium;    51,   Kalium ; 
52,  Ammonium. 

I. — NON-METALLIC   BODIES. 

(1)  Oxygen. — Although  this  element  occurs  so  abundantly  as  a 
constituent  of  mineral  bodies,  its  presence,  as  a  rule,  can  only  be 
inferred  by  negative  evidence.     If  a  substance  be  neither  one  of  the 
few  known  simple  bodies  of  natural  occurrence,  as  gold,  carbon,  &c., 
nor  a  sulphide,  selenide,  arsenide,  chloride,  &c.,  it  may  be  regarded 
with  tolerable  certainty  as  an  oxidized  body.     And  if,  farther,  its 
examination  shew  that  it  is  not  an  oxygen-salt,  i.e.,  a  sulphate,  car- 
bonate, silicate,  or  the  like,  we  can  then  only  infer  that  it  must  be  a 
simple  oxide,  either  electro-negative  or  basic  in  its  characters. 

All  non-oxidized  bodies  attackable  by  nitric  acid,  decompose  the 
latter  in  taking  oxygen  from  it,  and  thus  cause  the  evolution  of  ruddy 
nitrous  fumes;  but  this  decomposition  is  also  effected  by  certain 
oxides  in  passing  into  a  higher  state  of  oxidation,  as  by  Cu2O,  for 
example. 

Some  few  bodies,  as  binoxide  of  manganese,  nitrates,  chlorates, 
bichromates,  &c.,  give  off  oxygen  on  strong  ignition.  If  these  be 
ignited  (in  not  too  small  a  quantity)  in  a  test-tube  containing  at  its. 
upper  part  a  charred  and  feebly  glowing  match-stem,  the  latter,  as 
the  evolved  oxygen  reaches  it,  will  glow  more  vividly.  These  bodies, 
also,  if  fused  with  borax  or  phosphor-salt,  dissolve  with  strong  ebulli- 
tion ;  but  carbonates  produce  the  same  reaction. 

(2)  Hydrogen. — -This  element,  apart  from  its  occurrence  in  bitumen 
and  other  hydro-carbonaceous  substances,  is  only  present  in  oxidized 
minerals.     From  these,  it  is  evolved,  with  oxygen,  in  the  form  of 
water,  during  the  ignition  of  the  substance.    (See  Operation  2,  page  9.) 

(3)  Sulphur. — Occurs  in  the  free  state,  as  "native  sulphur;"  also 
combined  with  metals  in  sulphides  and  sulphur-salts ;  and  in  combina- 
tion with  oxygen,  as  SO3,  in  the  large  group  of  sulphates.     Native 
sulphur  is  readily  inflammable,  burning  with  blue  flame,  and  vola- 
tilizing (with  the  well  known  odour  of  burning  brimstone)  in  the; 


REACTIONS. 

\   e>       -    /^.       /.     <vx> 


' 


form  of  sulphurous  acid  SO2.  Metallic  sulphides  and  sulphur-salts 
(especially  if  previously  reduced  to  powder  and  moistenetl^intrf^  ^ 
paste),  when  roasted  in  an  open  tube  of  not  too  narroV^^eter,  ^  K 
give  off  the  same  compound  (SO2),  easily  recognized  by  its  oddtH^aB&l. 
by  its  action  on  a  slip  of  moistened  litmus  paper  placed  at  the  top  of 
the  tube,  the  paper  becoming  reddened  by  the  acid  fumes.  In  very 
narrow  (as  in  closed)  tubes,  part  of  the  evolved  sulphur  may  escape 
oxidation,  and  may  deposit  itself  011  the  inside  of  the  tube  near  the 
test-substance.  The  sublimate,  thus  formed,  is  distinctly  red  whilst 
hot,  and  yellow  on  cooling.  From  many  arsenical  and  antimonial 
sulphides  also,  a  coloured  sublimate  of  this  kind,  but  consisting  of 
As2S3,  or  2Sb2S3  -f  Sb203,  &c.,  may  be  deposited  in  narrow  tubes, 
especially  if  the  tube  be  held  more  or  less  horizontally. 

Sulphides  of  all  kinds,  if  fused  on  charcoal  with  carb.  soda  (or 
better,  with  carb.  soda  mixed  with  a  little  borax)  readily  form  an 
alkaline  sulphide  or  "  hepar."  This  smells,  when  moistened,  more  or 
less  strongly  of  sulphuretted  hydrogen,  and  imparts  a  dark  stain  to 
silver,  or  to  paper  previously  steeped  in  a  solution  of  lead  acetate. 
A  glazed  visiting  card  may  be  used  as  a  substitute  for  the  latter.  The 
stain  is  removed  from  the  silver  surface  by  friction  with  moistened 
boneash. 

Sulphates  fused  with  carb.  soda  and  a  little  borax  (the  borax  in  the 
case  of  earthy  sulphates  greatly  assisting  the  solvent  power  of  the  flux) 
produce  the  same  reaction.  This  reaction  is  of  course  produced 
also  by  sulphites  (which  do  not  occur,  however,  as  minerals),  and 
by  bodies  which  contain  selenium  in  any  form.  Sulphites,  treated 
with  hydrochloric  acid,  evolve  sulphurous  acid,  easily  recognized  by 
its  smell  and  its  action  on  litmus  paper ;  and,  in  acid  solutions,  they 
yield  no  precipitate  with  chloride  of  barium.  Sulphates,  on  the  other 
hand,  emit  no  odour  of  SO2  when  treated  with  hydrochloric  acid  ;  and 
chloride  of  barium  produces  an  insoluble  precipitate  in  their  acid 
or  other  solutions.  Bodies  containing  selenium,  are  distinguished 
from  sulphur  compounds  by  the  strong  odour,  resembling  that  of 
"  cabbage- water,"  which  they  evolve  on  ignition. 

The  efficacy  of  the  sulphur-test  is  imperilled  however  by  two 
causes :  (1),  the  difficulty,  in  many  places,  of  procuring  carbonate  of 
soda  perfectly  free  from  traces  of  sulphates ;  and  (2),  the  very  fre- 
quent presence  of  sulphur  in  the  flame,  where  gas  is  used  in  blow-- 


24  BLOWPIPE    PRACTICE.  * 

pipe  operations.  The  first  defect  may  be  remedied  (if  the  carb. 
soda,  employed  alone,  produce  the  reaction)  by  substituting,  as  pro- 
posed by  Plattner,  oxalate  of  potash  for  the  test,  as  that  salt  is 
generally  pure  and  free  from  sulphates;  and  the  flame  of  a  candle, 
or  an  oil  or  spirit-flame,  may  be  used  in  this  experiment,  when  the 
gas  flame  is  found  by  trial  with  pure  soda  or  oxalate  of  potash  to 
give  the  reaction. 

Sulphides  of  natural  occurrence  are  distinguished  from  sulphates, 
by  emitting  sulphurous  acid  (or,  strictly,  by  emitting  sulphur  vapour 
which  combines  with  atmospheric  oxygen  and  forms  sulphurous  acid) 
on  .ignition;  although  in  the  case  of  certain  sulphides  (blende, 
molybdenite,  <fec.)  a  strong  reaction  is  only  produced  by  the  ignition 
of  the  substance  in  powder.  Most  natural  sulphides,  also,  present  a 
metallic  aspect,  or  otherwise  are  highly  inflammable  (orpiment, 
cinnabar,  &c.),  or  yield  a  strongly-coloured  streak.  Light-coloured 
varieties  of  zinc  blende  are  the  only  exception.  On  the  other  hand, 
no  sulphate  possesses  a  metallic  aspect ;  and,  in  all,  the  streak  is 
either  colourless  or  very  lightly  tinted. 

(•1)  Selenium. — Met  with  only  in  a  few  minerals  of  very  rare 
occurrence.  In  these,  its  presence  is  revealed  by  the  formation  of  a 
"hepar"  with  carb.  soda,  and  simultaneous  emission  of  strongly- 
smelling  fumes,  the  odour  resembling  that  of  decaying  vegetable 
matters  or  "  cabbage  water."  In  volatilizing,  selenium,  like  sulphur, 
burns  with  a  blue  flame. 

(5)  Nitrogen. — Found   only,  as   regards   minerals   proper,  in  an 
oxidized  condition  (Ni2O5)  in  nitrates.      These  are  soluble  or  (as 
regards  certain  metallic  nitrates)   sub-soluble  in  water;   and  they 
deflagrate  when  ignited  on  charcoal  or  in  contact  with  other  carbo- 
naceous bodies.     Heated  with  a  few  drops  of  sulphuric  acid  (or  fused 
with  bisulphate  of  potash)  in  a  test-tube,  nitrates  evolve,  also,  ruddy 
fumes  of  nitrous  acid ;  and  many  nitrates,  moistened  with  sulphuric 
acid,  impart  a  dull  green  coloration  to  the  flame-border. 

(6)  Chlorine. — Occurs,    among    minerals,    in    combination    with 
various  bases,  forming  the  group  of  chlorides.     In  these,  its  presence 
is  very  easily  recognized  by  the  bright  azure-blue  coloration  of  the 


REACTIONS.  25 

flame-border  which  originates  during  the  fusion  of  a  chloride  with 
a  bead  of  phosphor-salt  coloured  by  oxide  of  copper.  The  fusion  may 
be  performed  on  a  loop  of  platinum  wire,  the  phosphor-salt  being  first 
fused  with  some  black  oxide  of  copper  into  a  somewhat  deeply 
coloured  glass,  and  the  test-substance,  in  the  form  of  powder,  being 
then  added.  Or  the  fusion  may  be  made  on  a  thin  copper-wire  with 
phosphor-salt  alone,  the  end  of  the  wire  being  cut  off  after  each 
experiment.  By  this  treatment,  chlorides  become  decomposed,  and 
chloride  of  copper  is  formed.  The  latter  compound  rapidly  volatilizes* 
and  imparts  a  remarkably  vivid  bright-blue  colour  to  the  flame.  The 
coloration  soon  passes,  but  can,  of  course,  be  renewed  by  the,  addition 
of  fresh  test-matter  to  the  bead.  Care  must  be  taken  to  use  pure 
phosphor-salt,  as  that  reagent,  unless  carefully  made,  is  frequently 
found  to  contain  traces  of  chloride  of  sodium. 

Oxidized  chlorine-compounds  do  not  occur  as  minerals,  but  it  may 
be  stated  that  chlorates  produce  the  same  flame-reaction  as  chlorides, 
when  fused  with  phosphor-salt  and  copper  oxide.  All  chlorates, 
Jiowever,  detonate  like  nitrates,  only  more  violently,  when  ignited  in 
contact  with  carbonaceous  bodies ;  and  they  turn  yellow,  decrepitate, 
and  emit  greenish  fumes  when  warmed  with  a  few  drops  of  sulphuric 
acid  (or  fused  with  bisulphate  of  potash)  in  a  test-tube.  The  fumes 
smell  strongly  of  chlorine,  and  bleach  moistened  litmus  paper. 
Chlorides,  when  thus  treated  with  sulphuric  acid,  effervesce  and  give 
off  white  fumes  of  hydrochloric  acid. 

(7)  Bromine. — Only  known,  among  minerals,  in  some  rare  silver 
bromides.  Its  blowpipe  reactions  closely  resemble  those  of  chlorine, 
but  the  flame-coloration  of  bromide  of  copper  is  a  bright  blue  with 
green  streaks  and  edges.  A  small  sharply-pointed  flame  is  required 
to  shew  the  reaction  properly ;  and  care  must  be  taken  not  to  add 
the  test-matter  to  the  cupreous  phosphor-salt  bead  until  all  traces  of 
the  green  coloration,  arising  from  the  oxide  of  copper,  have  disap- 
peared. Heated  in  a  test-tube  with  sulphuric  acid  (or  fused  with  large 
excess  of  bisulphate  of  potash)  bromides  yield  brownish  or  yellowish- 
red,  strongly  smelling  vapours  of  bromine.  Bromates  produce  the 
same  reaction,  but  this  is  accompanied  by  sharp  decrepitation ;  and 
when  fused  on  charcoal  they  detonate  more  or  less  violently.  (See 
Appendix,  No.  20). 


26 


BLOWPIPE    PRACTICE. 


(8)  Iodine. — In  nature,  occurs  only  in  one  or  two  rare  minerals, 
compounds  of  iodine  and  silver,  or  iodine,  silver,  and  mercury.     In 
these,  as  well  as  in  all  artificial  iodides,  its  presence  may  be  recognized 
by  the  vivid  green  coloration  imparted  to  the  flame  during  fusion 
with  a  cupreous  phosphor-salt  bead.     The  test-matter  must  not  be 
added  to  the  bead  until  the  copper  oxide  is  completely  dissolved  in 
the  latter,  and  all  traces  of  green  (communicated  by  the  CuO)  have 
disappeared  from  the  flame.      Iodides,  also,  when  warmed  with  a 
few  drops  of  sulphuric  acid  (or  fused  with  excess  of  bisulphate  of 
potash)    in   a   test-tube,    evolve    strongly    smelling    violet-coloured 
vapours,   which   impart  a  deep   blue    stain  to   matters   containing 
starch.     A  strip  of  moistened  tape  or  starched  cotton  may  be  held 
at  the  top  of  the  tube.     lodates  exhibit  the  same  reactions,  but 
deflagrate  when  ignited  with  carbonaceous  bodies.     (See  Appendix, 
No.  20). 

(9)  Fluorine. — This  element,  as  an  essential  component  of  minerals, 
occurs  in  combination  with  calcium  and  other  bases,  forming  the    * 
various  fluorides.     It  is  also  largely  present  in  topaz,  probably  in 
combination  with  silicon  and  aluminium ;  and  it  occurs,  though  in 
smaller  proportion,  in  chondrodite,  and  as  an  accidental  or  inessential 
component  in  many  other  silicates.     Its  presence  is  revealed  most 
readily,  by  warming  the  substance,  in  powder,  with  a  few  drops  of 
sulphuric  acid  (or  fusing  it  with  bisulphate  of  potash)  in  a  test-tube, 
when  stifling  fumes,  which  strongly  corrode  the  inside  of  the  glass, 
are  given  off.     Or,  the  trial  may  be  made  in  a  platinum  crucible 
covered  with  a  glass  plate :  on  washing  the  test-tube  or  glass,  and 
drying  it,  the  corrosion  is  rendered  visible.    When  fluorine  is  present 
in  very  small  quantity  in  a  substance,  it  is  generally  driven  off  the 
more  readily,  often  by  the  mere  ignition  of  the  substance  (either 
alone,  or  with  previously  fused  phosphor-salt)  at  one  end  of  an  open 
narrow  tube — the  flame  being  directed  into  the  tube,  so  as  to  decom- 
pose the  test-matter  and  drive  the  expelled  gases  before  it.     A  slip 
of  moistened  Brazil-wood  paper,  placed  at  the  mouth  of  the  tube,  is 
rendered  yellow.    Many  silicates  which  contain  only  traces  of  fluorine 
lose  their  polish  when  strongly  ignited,  in  the  form  of  a  small  splinter, 
per  se. 


REACTIONS.  27 

(10)  Phosphorus. — Occurs,  in  minerals,  in  an  oxidized  condition 
only,  i.e.,  as  phosphoric  acid  (or  anhydride)  in  the  group  of  phosphates.* 
As  first  pointed  out  by  Fuchs,  these  bodies,  when  moistened  with 
sulphuric  acid,  impart  a  green  coloration  to  the  flame-border,  and 
many  produce  this  reaction  per  se.  A  closely  similar  coloration, 
however,  is  communicated  to  the  flame  by  borates  (when  moistened 
with  sulphuric  acid),  as  well  as  by  bodies  containing  barium,  copper, 
&c.  It  only  serves,  therefore,  as  a  probable  indication  of  the  presence 
of  phosphoric  acid.  The  readiest  and  most  certain  method  of  detect- 

*  It  is  assumed  to  be  in  this  condition  simply  because  phosphates  give  the  known  reactions 
of  phosphoric  acid  or  phosphoric  anhydride,  although  these  reactions  may,  of  course,  be 
modified  to  some  extent  by  the  presence  of  other  bodies.  In  like  manner,  when  iron  is  present 
in  an  oxidized  body,  we  assume  that  it  is  present  in  the  condition  of  FeO  if  the  substance  give 
the  known  reactions  of  that  compound,  and  increase  in  weight  on  ignition ;  and  that  it  is 
present  as  Fe203  if  the  reactions  of  sesquioxide  of  iron  be  given  by  the  substance.  As  to  the 
actual  conditions,  either  physical  or  chemical,  of  bodies  in  combination,  we  know  absolutely 
nothing,  but  we  have  a  certain  knowledge  of  the  secondary  components  of  most  bodies.  We 
are  able  to  examine  these  components  apart,  and  to  form  more  complex  bodies  by  their  union. 
Thus,  from  a  piece  of  limestone  or  calcite  we  can  obtain  two  well  known  compounds,  lime  and 
carbonic  acid  (or  carbonic  anhydride) ;  and  with  these  compounds  we  can  readily  produce 
limestone  or  its  equivalent.  Hence,  the  simplest  and  most  practically  useful  way  of  stating, 
either  verbally  or  by  symbols,  the  composition  of  limestone  and  other  mineral  bodies,  is  surely 
that  which  makes  known  to  us  at  once  the  components  into  which  the  body  readily  splits  up 
or  decomposes,  or  which  characterize  it  directly  by  their  reactions.  This  method,  therefore,  is 
adhered  to  in  the  present  handbook.  It  may  be  urged  that  a  formula  of  the  kind  represented 
by  CaO,  CO2  asserts  too  much,  and  that  consequently  the  more  modern  Ca  CO3  is  preferable. 
But  rightly  considered,  the  old  formulae  need  not  be  assumed  to  make  any  assertions  regarding 
the  actual  condition  of  bodies  in  combination,  but  only  to  indicate  clearly  the  well  known 
simple  compounds  into  which  (in  the  great  majority  of  cases)  substances  may  be  more  or  less 
readily  decomposed,  and  the  reactions  which  substances  exhibit.  As  a  strict  matter  of  fact, 
moreover,  the  new  formulae  are  not  free  from  assertion.  They  carry  upon  their  face,  at  least, 
a  seeming  assertion  that  the  elementary  bodies  in  compounds  are  present  in  an  absolutely  free, 
separate  and  independent  state;  or  that  unknown  problematical  compounds,  as  CO 3,  SiO  4, 
SiO  5,  SiO  6,  etc.,  etc.,  are  present  in  the  substances  to  which  theso  formulae  refer.  To  take 
another  illustration.  A  student  has  two  minerals  before  him :  one  he  finds  to  be  the  well 
known  mineral,  corundum,  and  consequently  A1203  (alumina) ;  and  the  second  he  finds  to  be 
ordinary  quartz,  and  consequently  SiO2  (silica),  according  to  the  commonly  received  formula. 
He  has  also  before  him  a  third  mineral,  one  that  gives  the  reactions  of  alumina  and  silica,  and 
yields  these  separate  bodies  on  analysis.  Naturally,  therefore,  he  writes  the  formula  (assuming 
the  two  componen'ts  to  be  in  equal  atomic  proportions)  A1203,  SiO3.  But,  to  his  bewilderment, 
he  finds  it  given  in  modern  books  as  A12SK)5.  Practically,  we  do  not  want  te  know  how 
much  aluminium,  silicon  and  oxygen,  are  present  in  a  body  of  this  kind,  but  how  much  alumina 
and  silica  ;  and  the  first  formula  shews  us  this,  or  enables  us  to  determine  it  at  once.  Were 
only  simple  elements  and  their  complex  combinations  known  to  us,  the  new  views,  carried  out 
properly  to  their  full  conception,  might  pass  without  opposition ;  but  the  question  becomes 
entirely  altered  by  the  occurrence  of  simple  binary  compounds  so  abundantly  in  the  free  state. 
In  mineral  analysis,  and  in  the  practical  studjr  of  minerals,  it  is  not  possible  to  ignore  these 
binary  formulae  without  great  inconsistency.  Among  other  works,  they  are  retained  essentially, 
we  are  glad  to  find,  in  the  standard  and  very  copious  "  Handworterbuch  der  Chemie,"  now  being 
published  under  the  editorship  of  Dr.  Von  Fehling  of  Stuttgart.  See  also  Von  Kobell'a  remarks 
on  this  subject  in  the  5th  edition  of  his  "Mineralogie :"  1878. 


28  BLOWPIPE    PRACTICE. 

ing  the  latter,  is  to  boil  or  warm  the  powdered  substance  in  a  test-tube 
with  a  few  drops  of  nitric  acid,  and  after  half-filling  the  tube  with 
distilled  water,  to  drop  into  it  a  small  fragment  of  molybdate  of 
ammonia.  In  the  presence  of  phosphoric  acid,  this  will  turn  yellow 
immediately,  especially  if  the  solution  be  warmed,  and  a  canary  - 
yellow  precipitate  (soluble  in  ammonia)  will  rapidly  form.  All 
natural  phosphates,  with  the  exception  of  the  rare  phosphate  of  y  ttria, 
xenotime,  are  dissolved  or  readily  attacked  by  nitric  acid;  and 
xenotime,  if  in  fine  powder,  is  generally  attacked  sufficiently  to  yield 
the  reaction.  Phosphates  may  also  be  decomposed  by  fusion,  in  fine 
powder,  with  three  or  four  parts  of  carbonate  of  soda  in  a  platinum 
spoon  or  loop  of  platinum  wire.  An  alkaline  phosphate,  soluble  in 
water,  is  formed  by  this  treatment — with  xenotime  as  with  other 
phosphates — and  the  solution,  rendered  acid,  may  then  be  tested  by 
molybdate  of  ammonia.  Or  it  may  be  rendered  neutral  by  a  drop  of 
acetic  or  very  dilute  nitric  acid,  and  tested  with  a  fragment  of  nitrate 
of  silver,  in  which  case  a  canary-yellow  precipitate  will  also  be  pro- 
duced. Or  it  may  be  tested  by  adding  to  it  a  small  fragment  or  two 
of  acetate  of  lead,  and  fusing  the  resulting  precipitate  on  charcoal. 
On  cooling,  the  surface  of  the  fused  bead  shoots  into  crystalline  facets. 

(11)  Boron. — Present  in  nature  in  an  oxidized  condition  only,  as 
boracic  acid.  This  occurs  :  (1),  in  the  hydrated  state;  (2),  in  combi- 
nation with  bases,  in  the  group  of  borates ;  and  (3),  in  certain  so- 
called  boro-silicates.  Boracic  acid  (or  anhydride)  and  many  borates 
and  boro-silicates  impart  per  se  a  green  coloration  to  the  flame-border, 
and  all  produce  this  coloration  if  previously  saturated  with  sulphuric 
acid.  In  some  few  silicates,  however,  in  which  little  more  than  traces 
of  BO3  are  present,  the  reaction  is  scarcely  or  only  very  feebly 
developed  unless  the  test-substance,  in  fine  powder,  after  treatment 
with  sulphuric  acid,  and  partial  desiccation,  be  moistened  with 
glycerine,  according  to  a  process  first  made  known  by  lies.  But  a 
similar  flame-coloration  is  produced  by  phosphates  and  certain  other 
bodies.  For  the  proper  detection  of  borates,  therefore,  the  following 
long-known  method  should  be  resorted  to.  The  test-matter,  in  fine 
powder,  is  saturated  with  sulphuric  acid,  and  allowed  to  stand  for  a 
minute  or  two;  a  small  quantity  of  alcohol  is  then  added,  and  the 
mixture  is  stirred  and  inflamed.  The  presence  of  BO3— unless  in 


REACTIONS.  29 

very  minute  or  accidental  quantity — •communicates  to  the  point  and 
edges  of  the  flame  a  peculiar  green  or  yellowish-green  colour.  Phos- 
phates do  not  colour  the  flame  under  this  treatment. 

(12)  Carbon. — Occurs  in  the   simple   state  in  the  diamond   and 
graphite,  and  practically  so  in  the  purer  kinds  of  anthracite ;  also 
combined  with  hydrogen,  &c.,  in  ordinary  coals  and  bituminous  sub- 
stances ;  and  in  an  oxidized  condition,  as  carbonic  acid  (or  anhydride) 
in  the  group  of  carbonates.     Free  (mineral)  carbon  is  infusible  and 
very  slowly  combustible  in  the   blowpipe-flame,  a  long   continued 
ignition  being  necessary  to  effect  the  complete  combustion  of  even 
minute  splinters.     Ignited  with  nitre,  it  deflagrates  and  is  dissolved, 
carbonate  of  potash  resulting.     "With  other   blowpipe  reagents  it 
exhibits  no  characteristic  reactions.     The  presence  of  carbonic  acid 
in  carbonates  is  readily  detected  by  the  effervescence  which  ensues 
during  the  fusion  of  a  small  particle  of  the  test-substance  with  a 
previously-fused  bead  of  borax  or  phosphor-salt  on  platinum  wire, 
CO2  being  expelled.       All  carbonates,  even  in  comparatively  large 
fragments,  dissolve  readily  under  continued  effervescence  in  these 
fluxes.     A  mixture  of  carbonate  of  lime  in  silicates,  sulphates,  and 
other  bodies,  may  thus  be  easily  recognized.     (See  Appendix,  No.  19), 
It  should  be  remembered,  however,  that  bodies  which  evolve  oxygen 
on  ignition,  produce  also  a  strong  effervescence  by  fusion  with  borax  • 
but,  with  the  exception  of  binoxide  of  manganese,  very  few  of  these 
bodies  are  of  natural  occurrence. 

(13)  Silicon. — This  element  occurs  in  nature  only  io  an  oxidized 
condition,  as  Silica,  SiO2.     The  latter  compound,  in  the  form  of 
quartz  and  its  varieties,  is  the  most  widely  distributed  of  all  min- 
erals.    In  the  various  opals,  it  occurs  combined  with  water,  and  in 
combination  with  bases  (especially  with  A1203,  Fe203,  CaO,  MgO, 
FeO,  Na2O,  and  K20),  it  forms  the  large  group  of  silicates.     In  the 
simple  state,  silica  is  quite  infusible  in  the  ordinary  blowpipe-flame. 
With  carb.  soda,  it  dissolves  with  effervescence  (due  to  the  expulsion 
of  CO2  from  the  flux),  and  it  forms  with  that  reagent,  in  proper  pro- 
portions, a  permanently  clear  glass — i.e.,  a  glass  that  remains  clear 
on  cooling.     To  obtain  this,  the  flux  should  be  added  little  by  little, 
until  perfect  fusion  ensue:  with  too  much  soda,  the  bead  is  opaque. 


30  BLOWPIPE   PRACTICE. 

Borax  attacks  silica  very  slowly,  and  in  phosphor-salt  it  is  still  more 
slowly  attacked.  A  portion  may  be  taken  up  by  the  hot  glass,  but 
this  is  precipitated  on  cooling,  and  the  glass  becomes  opalescent. 
(See  Appendix,  No.  15).  Silicates  vary  greatly  in  their  comport- 
ment before  the  blowpipe,  the  variation  depending  chiefly  on  the 
relative  proportions  of  silica  and  base,  and  on  the  nature  of  the  base. 
Many  silicates  are  infusible ;  others  become  vitrified  on  the  thin 
edges;  and  others,  again,  melt  more  or  less  readily, — most  of  the 
so-called  zeolites  (hydrated  silicates  of  alumina,  lime,  soda,  &c.,  espe- 
cially characteristic  of  trap  rocks)  exhibiting  the  phenomenon  of 
intumescence.  Silicates,  as  a  rule,  are  very  readily  detected  by  their 
comportment  with  phosphor-salt :  the  bases  are  gradually  taken  up, 
whilst  the  silica  remains  for  the  greater  part  undissolved,  forming  a 
"  silica-skeleton/'  This  is  seen  as  a  diaphanous,  flocculent  mass  (of 
the  shape  and  size  of  the  test-fragment)  in  the  centre  of  the  hot  bead. 
A  small  portion  of  the  silica,  or  in  one  or  two  exceptional  cases  the 
greater  part  of  it,  may  be  dissolved  with  the  bases,  but  this  precipi- 
tates as  the  glass  cools,  and  renders  it  vsemi- translucent  or  opalescent. 
Practically,  silicates  are  readily  distinguished  from  phosphates,  car- 
bonates, sulphates,  <fec.,  by  these  reactions  with  phosphor-salt :  namely, 
very  slow  or  partial  solution,  and  formation  in  most  cases  of  a  silica 
skeleton  or  opalescent  glass.  The  trial  is  best  made  on  platinum 
wire,  and  the  test-substance  should  be  added,  if  possible,  in  the  form 
of  a  thin  scale  or  splinter.  (See  Appendix,  No.  15). 

II. — UNOXIDIZABLE   METALS. 

As  regards  their  blowpipe  reactions,  the  metals  of  this  group  fall 
into  two  series :  Infusible  metals,  comprising  platinum  (with  palladium, 
<fec. ) ;  and  Fusible  metals,  comprising  gold  and  silver.  Strictly,  silver 
absorbs  a  small  amount  of  oxygen  when  fused  in  contact  with  the 
atmosphere,  but  the  oxygen  is  evolved  as  the  metal  solidifies.  It  is 
this  which  causes  cupelled  silver  to  "  spit "  or  throw  out  excrescences, 
if  the  button  be  allowed  to  cool  too  quickly.  All  the  metals  of  this 
group  (palladium  slightly  excepted)  retain  a  bright  surface  when 
exposed  to  the  action  of  an  oxidating  flame. 

(14)  Platinum. — Occurs  in  the  metallic  state,  alloyed  with  indium, 
«,nd  commonly  with  small  quantities  of  other  metals.  Practically, 


REACTIONS.  81 

infusible ;  but  the  point  of  a  wire  of  extreme  tenuity  may  be  rounded 
in  a  well-sustained  flame.     Not  attacked  by  the  blowpipe  fluxes. 

(15)  Gold. — Occurs  principally  in  the  metallic  state,  alloyed  with 
variable  proportions  of  silver.     Also,  but  far  less  commonly,  com- 
bined with  mercury  in  some  varieties  of  native  amalgam,  and  with 
tellurium  in  some  rare  tellurides.     In  the  metallic  condition,  or  per* 
haps  as  an  arsenide  or  sulphide,  it  is  present  likewise  as  an  accidental 
component  in  many  examples  of  arsenical  pyrites,  iron  pyrites,  copper 
pyrites,  zinc  blende,  &c.,  in  the  proportions  of  a  pennyweight  or  two, 
to  several  ounces,  per  ton.     Fuses  readily  on  charcoal  before  the 
blowpipe,  and  retains  its  bright  surface  in  an  oxidating  flame*     Not 
attacked  by  the  blowpipe  fluxes.     Separated  from  silver  by  fusion 
with  bisulphate  of  potash  in  a  platinum  spoon,  the  silver  becoming 
dissolved,  or  (if  the  silver  be  not  in  too  small  a  quantity)  by  dilute 
nitric  acid  moderately  warmed.     In  the  latter  treatment,  the  gold 
separates  as  a  dark  mass  or  powder.    This  assumes  a  yellow  colour  and 
metallic  lustre  by  compression  with  a  glass  rod  or  other  hard  body. 
An  alloy  of  gold  containing  but  little  silver  is  merely  blackened  by 
the  acid.     In  this  case  it  may  be  folded  in  a  small  piece  of  pure  sheet 
lead  with  a  piece  of  silver  of  about  twice  or  three  times  its  size,  and 
cupelled  before  the  blowpipe  (Operation  9,  page  19).     The  alloy  is 
then  readily  attacked  by  the  acid,  and  the  silver  is  dissolved  out* 

(16)  Silver.—  This  metal  occurs  in  nature  under  various  conditions : 
principally  in  the  simple  state,  as  an  amalgam  with  mercury,  and  as 
a  sulphide,  sulphantimonite,  sulpharsenite,  and  chloride;  less  com* 
monly  as  a  selenide,  telluride,  antimonide,  sulpho-bismuthite,  bromide 
and  iodide.     It  occurs  also  as  an  "  accidental  component "  in  many 
varieties  of  iron  pyrites,  <fec.>  and  in  almost  every  example  of  galena.* 
Metallic  silver  melts  readily  before  the  blowpipe,  and  the  fused  globule 
retains  a  bright  surface  after  exposure  to  an  oxidating  flame.     In  a 
prolonged  blast  a  slight  brownish-red  sublimate  is  deposited  on  the 
charcoal,  the  sublimate  being  more  distinctly  red  in  the  presence  of 
lead  or  antimony,  but  in  the  latter  case  it  is  scarcely  observable  until 
these  metals  become  for  the  greater  part  volatilized.     Silver  oxide 
becomes  rapidly  reduced  on  charcoal.     It  is  dissolved  by  borax  and 
phosphor  salt,  forming  glasses  which  are  indistinctly  yellowish  whilst 

\  ~  J    ~  ** 

*  For  its  detection  in  this  mineral,  see  the  foot  note  on  page  19. 


BLOWPIPE   PRACTICE. 

hot,  and  opaline  or  opaque-white  on  cooling.  Metallic  silver  is 
attacked  with  similar  results  by  these  fluxes,  and  also  by  bisulphate 
of  potash.  In  all  ordinary  cases  the  presence  of  silver  in  minerals  is 
best  detected  by  reduction  and  cupellation  with  lead,  as  described 
under  Operations  8  and  9,  pages  16-20,  above.  Or  a  kind  of  scorifi- 
cation  process  may  be  employed,  by  mixing  the  unroasted  ore  (to 
avoid  loss  of  silver)  with  a  little  borax,  and  fusing  it  in  a  small 
cylindrical  case  of  pure  lead-foil,  made  by  folding  a  piece  of  foil 
round  the  end  of  a  common  pencil,  and  flattening  down  the  projecting 
edges.  The  mixture  is  inserted  into  this  little  case  by  a  folded  slip 
of  glazed  paper,-  or  a  small  scoop  of  horn  or  thin  brass.  The  upper 
edges  of  the  foil  being  then  pressed  or  flattened  down,  the  case  with 
its  contents  is  sunk  in  a  sufficiently  deep  charcoal-cavity,  and  exposed 
for  a  few  minutes,  first  to  a  reducing,  then  to  an  oxidating,  and  then 
again  to  a  reducing  flame,  until  the  rotating  globule  shew  a  clean, 
bright  surface.  If  the  metallic  button,  after  separation  on  the  anvil 
from  accompanying  slag,  be  too  large  to  be  cupelled  in  one  operation, 
it  may  be  flattened  out  and  cut  into  several  pieces.  These  can  be 
concentrated  on  separate  cupels,  and  then  cupelled  together  as 
described  at  page  19. 

III.— VOLATILIZABLE    METALS. 

* 

The  metals  of  this  group  are  characterized  (tin  excepted)  by  the 
emission  of  more  or  less  copious  fumes  when  ignited  before  the  blow- 
pipe. Tin  becomes  rapidly  coated  with  a  crust  of  oxide,  and  is  only 
slightly  volatile.  In  arsenic  and  osmium  the  evolved  fumes  are  accom- 
panied by  a  marked  odour.  Tellurium,  antimony,  arsenic,  bismuth, 
lead,  thallium,  cadmium  and  zinc,  form  characteristic  sublimates  on 
charcoal,  and  (cadmium  and  bismuth  excepted)  these  metals  impart 
a  marked  coloration  to  the  flame-border.  Tin  forms  only  a  slight 
sublimate.  Lead,  thallium  and  tin  give  malleable  globules;  tellurium, 
antimony  and  bismuth,  brittle  globules.  The  other  metals  of  the 
group  volatilize  without  fusion,  or  without  yielding  metallic  globules 
011  charcoal. 

(17)  Tellurium. — This  metal  is  of  rare  occurrence.  It  is  found 
occasionally  in  the  simple  state,  and  also  combined  with  gold,  silver, 
lead,  and  other  bases  in  the  small  group  of  tellurides.  The  metal 
fuses  easily,  volatilizes,  tinges  the  flame  green,  and  forms  a  white 


REACTIONS. 

deposit  of  TeO2  on  charcoal.  In  the  open  tube,  TeO2  is 
as  a  white  coating,  but  this,  when  the  flame  is  directed 
into  small  colourless  drops,  a  character  by  which  it  is 
from  the  sublimate  formed  by  antimony  and  antimonial  compounds,- 
Tellurides  produce  the  same  general  reactions.  The  presence  of 
tellurium  may  also  be  recognized  by  fusing  the  test-matter  with  carb. 
soda  on  charcoal,  cutting  out  the  fused  mass,  and  dissolving  the 
resulting  alkaline  telluride  in  hot  water.  The  solution  has  a  dis- 
tinct reddish-purple  colour.  A  purple  (or  reddish)  coloration  is  also 
obtained  by  warming  the  test-substance,  in  powder,  with  concentrated 
sulphuric  acid. 

(18)  Antimony. — Occurs  in  nature  (though  rarely)  in  the  simple 
state,  and  in  one  or  two  rare  antimonides.  Also  much  more  abundantly 
in  combination  with  sulphur ;  and  as  a  sulphur- acid  in  combination 
with  lead,  copper^  and  other  bases,  in  the  somewhat  extensive  group 
of  sulphantimoiiites.  It  also  occurs  in  an  oxidized  condition,  but  in 
that  state  is  comparatively  rare.  The  presence  of  antimony  is- 
revealed  in  these  minerals  by  the  emission  of  copious  white  fumesr 
with  deposition  of  a  white  coating  on  charcoal,  and  green  coloration 
of  the  flame.  The  white  coating  if  moistened  with  nitrate  of  cobaltr 
and  gently  ignited,  assumes  on  cooling  a  greenish  colour.  By  treat- 
ment in  the  open  tube,  a  dense  white,  or  greyish-white,  uncrystalline 
sublimate  is  produced.  This  is  soluble  in  tartaric  acid.  If  a  bead 
of  sulphide  of  sodium  (obtained  by  the  fusion  of  some  carb.  soda  with 
a  little  borax  and  some  bisulphate  of  potash  in  a  reducing  flame  on 
charcoal)  be  placed  in  the  solution,  an  orange-red  precipitate  (Sb'2S3) 
is  produced.  (See  Appendix,  No.  13.)  Sulphantimonites  are  par- 
tially dissolved  by  a  solution  of  caustic  potash.  Hydrochloric  acid 
throws  down  from  the  solution  the  same  orange-coloured  precipitate 
of  Sb2S3.  Antimonial  oxides  dissolve  readily  in  borax  and  phosphor- 
salt,  forming  beads  which  are  slightly  yellowish  or  colourless  after 
exposure  to  an  oxidating  flame,  and  grey,  from  reduced  particles  of 
metal,  when  exposed  to  the  R.  F.  Prolonged  blowing,  however, 
causes  the  metal  to  volatilize,  and  the  glass  becomes  clear.  The 
phosphor-salt  bead  treated  with  tin,  becomes  on  cooling  dark  grey  or 
black,  and  quite  opaque.  This  reaction  is  characteristic  of  antimony 
and  bismuth  compounds. 
4 


34  BLOWPIPE    PRACTICE. 

(19)  Arsenic. — Occurs,  more  especially,  under  the  following  con- 
ditions :  In  the  simple  metallic  state  (usually  impure  from  the 
presence  of  small  quantities  of  Sb,  Fe,  Co,  &c.).  In  various  arsenides, 
combined  chiefly  with  cobalt,  nickel,  and  iron.  In  combination  with 
sulphur,  alone,  and  combined  with  bases  (Ag,  Cu,  &c.),  forming  a 
small  series  of  sulpharsenites.  In  combination  with  oxygen,  as 
arsenic  acid,  alone,  and  combined  with  CuO,  NiO,  and  other  bases 
forming  the  various  arseniates.  In  these  conditions  its  presence,  as  a 
rule,  is  easily  recognized  by  the  strong  odour  of  garlic  evolved  during 
the  ignition  of  the  mineral  on  charcoal.  In  substances  of  a  non- 
metallic  aspect,  the  odour  is  more  strongly  developed,  if  the  test- 
matter  be  mixed  with  carb.  soda.  Metallic  arsenic  sublimes,  without 
melting,  in  copious  fumes,  which  form  a  white  or  grayish  deposit  on 
the  charcoal.  A  clear  blue  tint  is  communicated  at  the  same  time  to 
the  flame-border.  Similar  fumes  are  also  emitted  (though  less  copi- 
ously) by  most  arsenides  and  sulpharsenites,  as  wtll  as  by  oxidized 
compounds,  as  the  arsenic  acid  of  the  latter  is  readily  reduced  on 
charcoal.  Non-oxidized  arsenical  bodies  when  ignited  in  the  open 
tube  (Operation  5,  page  11),  evolve  arsenic,  which  becomes  oxidized 
into  arsenious  acid  As2O3,  by  the  current  of  air  passing  up  the  tube ; 
and  this  compound  is  in  great  part  deposited  in  the  form  of  minute 
crystals  (octahedrons),  a  short  distance  above  the  test-matter.  If  the 
tube  be  of  very  narrow  diameter,  however,  or  if  it  be  held  too  hori- 
zontally, a  gray  or  black  deposit  of  metallic  arsenic,  or  a  yellow  or 
red  deposit  of  sulphide  of  arsenic,  may  also  be  formed.  The  crystals, 
although  very  minute,  can  generally,  from  their  glittering  facets,  be 
recognized  by  the  unaided  eye,  but  a  strong  magnifying  glass  or  small 
microscope  is  required  for  their  proper  observation.  All  arsenical 
bodies,  either  per  se,  or  when  mixed  with  dry  carb.  soda,  neutral 
oxalate  of  potash,  or  other  reducing  agents,  and  ignited  in  a  narrow 
tube  closed  at  one  end,  form  a  dark  shining  "mirror"  on  the  inside 
of  the  neck  of  the  tube.  The  reaction  is  assisted  in  the  case  of  oxi- 
dized bodies  which  contain  merely  a  small  amount  of  arsenic,  by 
placing  a  charred  match  or  slip  of  charcoal  in  the  tube,  above  the 
assay-mixture,  and  igniting  first  the  charcoal  and  then  the  mixture, 
so  as  to  drive  the  fumes  over  the  charcoal.  A  dark  metallic  ring  is 
formed  by  this  method,  even  if  the  test-substance  contain  only  traces 
of  arsenic ;  and  if  the  charcoal  be  shaken  out  of  the  tube,  held  against 


REACTIONS.  35 

the  side. of  the  flame  until  ignited,  and  then  brought  quickly  under 
the  nose,  the  presence  of  the  slightest  trace  becomes  revealed  by  the 
characteristic  garlic-like  odour  which  is  then  emitted. 

Non-oxidized  arsenical  minerals  possess  a  metallic  aspect,  or,  in 
default  of  this,  are  readily  inflammable.  Arseniates,  on  the  other 
hand,  never  present  a  metallic  lustre,  and  none  are  inflammable. 
Many  cupreous  arseniates  deflagrate  strongly  when  ignited  011 
charcoal.  Arsenic  acid,  As205  (both  alone,  and  in  some  arseniates), 
gives  off  oxygen  on  strong  ignition,  and  becomes  volatilized  in  the 
condition  of  As203. 

(20)  Osmium. — -This  metal  is  of  quite  exceptional  occurrence.     It 
is  found  in  only  one   mineral,  Osinium-Iridium,  and  is   thus  often 
classed  as  a  so-called  "platinum  metal;"  but  its  general  characters 
and  reactions  give  it  a  place  near  arsenic.     Osmium -Iridium  remains 
unchanged  before  the  blowpipe,  unless  the  osmium  greatly  prepon- 
derate (as  in  the  variety  known  as  sisserskite),  in  which  case  part  of 
the  osmium  is  volatilized.     All  varieties  when  fused  with  nitre  in 
the  closed  tube  or  on  charcoal,  emit  the  penetrating  disagreeable 
odour  of  osmic  acid.      Osmium,   itself,   volatilizes   without  fusing, 
emitting  necessarily  the  same  odour ;  and  in  a  finely  divided  state  it 
is  inflammable.     If  volatilized  in  the  pale  flame  of  alcohol,  or  that  of 
the  Bunsen  burner,  it  renders  the  flame  highly  luminous. 

(21)  Mercury. — Occurs  sparingly  in  the  simple  state;  in  silver 
and  gold  amalgams ;  and  in  certain  seleiiides.     More  abundantly  as 
a  sulphide — Cinnabar,  the  only  ore  of  mercury.*     Sparingly,  also,  in 
some  varieties  of  grey  copper  ore  (tetrahedrite) ;  and  in  combination 
with  chlorine,  in  native  calomel.     In  these  compounds,  its  presence 
may  be  readily  ascertained  by  mixing  the  test-matter  with  some 
perfectly  dry  carb.  soda,  iron  filings,  neutral  oxalate  of  potash,  or 
other  reducing  substance,  and  igniting  the  mixture  in  a  closed  tube 
of  narrow  diameter.     The  metal  volatilizes,  and  deposits  itself  on  the 
neck  of  the  tube  in  the  form  of  a  dark  grey  sublimate.     If  this  be 
rubbed  by  an  iron  wire,  it  runs  into  fluid  globules  which  can  be 

*  Red  ochre  is  frequently  mistaken  by  explorers  for  cinnabar.  Apart  from  the  high  sp.  gr. 
of  the  latter,  the  two  may  be  easily  distinguished  by  an  ignited  lucifer  match.  Held  (in  the 
form  of  a  small  fragment)  in  the  match  flame,  cinnabar  takes  fire  and  volatilizes ;  red  ochre 
blackens  and  becomes  magnetic. 


36  BLOWPIPE    PRACTICE. 

poured  out  of  the  tube,  and  which  are  easily  recognized  as  metallic 
mercury.  Without  the  reducing  agent,  many  of  these  mercurial 
compounds  (cinnabar,  calomel,  &c.)  sublime  without  or  with  only 
partial  decomposition.  When  mercury  is  present  in  traces  only,  a 
piece  of  gold-leaf,  twisted  rqund  an  iron  wire  or  glass  rod,  may  be 
inserted  into  the  mouth  of  the  flask.  The  gold  is  whitened  by  a 
mere  trace  of  the  volatilized  metal. 

(22)  Bismuth. — Occurs  in  nature  chiefly  in  the  simple  metallic 
state.  Found  also,  but  more  sparingly,  in  combination  with  tellu- 
rium, selenium,  and  sulphur,  and  with  bases  in  sulpho-bismuthites. 
Occasionally,  likewise,  in  an  oxidized  condition  (Bi203)  as  bismuth 
ochre  (commonly  mixed  with  some  carbonate  of  bismuth),  and  in  a 
single  rare  silicate,  arseniate,  and  vanadiate.  Metallic  bismuth  fuses 
readily,  and  gradually  volatilizes,  depositing  a  dark  yellow  ring  of 
oxide  on  the  charcoal.  The  latter  volatilizes  in  the  inner  flame 
without  colouring  the  flame-border.  Bismuth  oxide  is  at  once 
reduced  and  volatilized  on  charcoal.  It  dissolves  in  carb.  soda  in 
an  oxidating  flame,  very  readily,  if  a  platinum  wire  or  other  non- 
reducing  support  be  used.  The  glass  is  yellow  or  yellowish-brown 
whilst  hot,  pale  yellow  and  opaque  when  cold.  In  borax  and  phos- 
phor-salt, it  dissolves  also  readily.  The  borax  glass  in  the  O.  F.  is 
yellowish,  hot,  and  very  pale  yellow  or  white  aud  opaline  when 
cold.  In  the  R.  F.  the  glass  becomes  clear  from  separation  of  the 
reduced  metal.  The  phosphor-salt  glass  in  the  O.  F.  may  be  rendered 
milk-white  by  flaming  or  saturation.  In  the  R.  F.,  with  tin,  it  is 
transparent  whilst  hot,  and  very  dark-grey  or  black  on  cooling.  In 
this  respect,  the  reaction  resembles  that  produced  by  antimony.  The 
presence  of  bismuth,  in  bodies  generally,  is  detected  by  the  dark -yellow 
coating  or  ring-deposit  formed  on  charcoal  by  the  fusion  or  ignition  of 
the  test-substance  with  carb.  soda.  This  deposit  is  distinguished  from 
that  formed  by  lead,  by  its  deeper  colour,  and  by  imparting  no  colour 
to  the  flame.  Also,  by  the  black  bead  formed  by  it  (or  by  another 
portion  of  the  test-substance)  with  phosphor-salt  and  tin  in  a  reducing 
flame,  as  described  above.  The  button  of  reduced  bismuth,  moreover, 
is  brittle ;  that  of  lead,  malleable.  These  metals  may  also  be  dis- 
tinguished by  the  sublimates  which  they  form  when  ignited  on 
charcoal  with  iodide  of  potassium,  according  to  the  method  of  Merz ; 


REACTIONS.  37 

or  by  fusion,  first  with  sulphur,  and  then  with  iodide  of  potassium, 
according  to  the  more  delicate  process  of  Yon  Kobell.  With  lead, 
the  sublimate  is  lemon-yellow,  or  in  thin  layers,  greenish-yellow ; 
whilst  with  bismuth  it  presents  a  vivid  scarlet  colour,  or  a  ring  of 
this  around  the  outer  edge  of  a  yellowish  deposit.  When  a  very 
small  amount  of  bismuth  oxide  is  associated  with  excess  of  lead  oxide, 
Cornwall  recommends  a  modification  of  the  process,  as  follows  :  the 
substance,  mixed  with  about  an  equal  quantity  of  a  mixture  of  five 
parts  sulphur  and  one  part  iodide  of  potassium,  is  ignited  in  a  test- 
tube  by  the  spirit-flame  or  bunsen  burner.  The  presence  of  bismuth 
is  indicated  by  a  scarlet  or  orange-coloured  band,  which  forms  above 
the  yellow  sublimate  occasioned  by  the  lead.  (See,  also,  page  67,  the 
characteristic  reaction  with  hydriodic  acid,  lately  discovered  by  Dr. 
Haanel.) 

(23)  Lead. — The  occurrence  of  native   lead  is  quite  exceptional. 
The  metal  occurs  most  commonly  as  a  sulphide  (galena),  and  not 
uncommonly  as  a  sulphantimonite  (and  to  some  extent  as  a  sulph- 
arsenite).     Also,  frequently  in  an  oxidized  condition,  as  a  sulphate, 
carbonate,   phosphate  and   arseniate.     Among  rarer  (natural)  com- 
pounds, it  occurs  as  a  selenide,  telluride,  chloride,  oxide,  chromate, 
vanadiate,  tungstate,  molybdate,  antimoniate.     The  presence  of  lead 
in  bodies  generally  is  made  known  in  blowpipe  testing  by  the  two 
following   characters :    the  formation   of   a  yellow  ring-deposit   on 
charcoal,  and  the  ready  formation  of  a  malleable  metallic  globule — 
these  reactions  requiring,  however,  in  some  few  cases,  the  assistance 
of  carb.  soda  or  other  reducing  flux  for  their  proper  manifestation.* 
Lead  oxide  is  immediately  reduced  on  charcoal,  colouring  the  flame 
light-blue.     It  dissolves  readily  in  the  blowpipe  fluxes  if  the  fusion 
be  performed  on  a  non-reducing  support.     The  glasses,  produced  by 
an  oxidating  flame,  are  colourless  or  yellowish,  and  become  opaque 
by  saturation  or  flaming.     (See  Appendix,  No.  6.) 

(24)  Thallium. — This  new  metal  is  only  known  to  occur  (in  very 
minute  quantities)  in  certain  examples  of  iron  pyrites,  copper  pyrites, 
zinc  blende,  native  sulphur,  and  some  few  other  minerals.     Its  chief 
characteristic  is  its  property  of  imparting  a  brilliant  green  coloration 

*  In  the  presence  of  sulphur,  more  especially,  the  reduction  is  facilitated  by  the  addition  of 
a  small  piece  of  iron  wire.     See  note  at  foot  of  page  19. 


38  BLOWPIPE    PRACTICE. 

to  the  Bimsen  or  blowpipe  flame.  In  other  respects  its  reactions 
much  resemble  those  of  lead,  but  the  oxidized  ring-deposit  (best  seen 
on  a  porcelain  support  or  on  the  surface  of  a  boneash  cupel)  is  dark 
brown.  (See  Appendix,  No.  14). 

(25)  Cadmium. — As  an  essential  component,  this  metal  occurs 
only  in  a  rare  sulphide,  greenockite.  It  is  present,  however,  in  small 
quantity  in  many  examples  of  zinc  blende,  and  in  certain  varieties 
of  the  carbonate  and  silicate  of  zinc.  Metallic  cadmium,  on  charcoal 
before  the  blowpipe,  shrinks  somewhat  together,  blackens,  takes  fire 
slightly,  and  becomes  volatilized  in  dense  brown  fumes.  These 
deposit  themselves  in  the  form  of  a  brownish-black  and  reddish- 
brown  coating  (CdO),  with  a  tinge  of  brownish-yellow  towards  the 
outer  edge.  The  deposit  is  at  once  reduced  and  dissipated  by  either 
flame,  without  communicating  any  colour  to  the  flame  border.  In 
both  the  closed  and  open  tube,  if  the  latter  be  of  narrow  diameter,  a 
metallic  sublimate  is  formed  near  the  assay -matter,  and  a  dark-brown 
sublimate,  with  yellowish  edge,  higher  up  the  tube.  Fused  with 
phosphor-salt  on  charcoal,  metallic  cadmium  (like  metallic  zinc)  gives 
rise  as  the  bead  cools  to  slight  detonations  and  flashes  of  light. 
Cadmium  oxide  011  a  non-reducing  support  is  infusible,  and  remains 
unvolatilized.  With  borax  and  phosphor-salt  it  forms  colourless 
beads  which  become  milk-white  and  opaque  by  saturation  or  flaming. 
On  charcoal  the  oxide  is  rapidly  reduced  and  volatilized,  but  yields 
no  metallic  globule.  The  dark  red -brown  sublimate,  formed  on  char- 
coal or  better  on  a  porcelain  support  by  the  fusion  of  a  cadmiferous 
substance  with  carb.  soda,  is  the  principal  blowpipe-reaction  of  the 
metal.  In  the  presence  of  much  zinc,  the  blast  must  not  be  con- 
tinued too  long,  otherwise  the  dark  deposit  of  cadmium  oxide, 
formed  before  the  deposition  of  the  zinc  oxide,  may  be  obscured 
by  the  lattar.  For  the  detection  of  cadmium  in  the  presence  of  zinc 
generally,  see  Appendix,  No.  17. 

(26)  Zinc. — Of  doubtful  occurrence  in  the  native  state.  Found 
principally  as  a  sulphide,  oxy-sulphide,  oxide,  sulphate,  carbonate, 
silicate  and  aluminate.  Metallic  zinc,  when  ignited  on  charcoal, 
burns  vividly  with  transient  flashes  of  green,  blue  and  greenish-white 
flame,  and  throws  off  dense  fumes  which  become  oxidized  and 
deposited  as  a  coating  on  the  charcoal.  This  coating  (ZnO)  is  palo" 


REACTIONS.  39 

yellow  and  phosphorescent  when  hot,  and  white  when  cold.  It  is 
not  driven  off  by  the  reducing  flame,  unless  the  blast  be  long  con- 
tinued. If  moistened  with  a  drop  or  two  of  nitrate  of  cobalt,  and 
ignited  by  an  oxidating  flame,  it  becomes  of  a  light-green  colour  on 
cooling.  Zinc  oxide  forms  with  borax  and  phosphor-salt  colourless 
beads,  which  become  milk-white  and  opaque  by  saturation  or  when 
flamed.  Metallic  zinc  fused  with  a  bead  of  phosphor-salt  on  char- 
coal, detonates  slightly  and  emits  flashes  of  light  after  removal  from 
the  flame — a  reaction  first  noticed  by  Wohler,  and  considered  to  arise 
from  the  formation  of  a  zinc  phosphide.*  It  is  manifested,  however, 
not  only  by  zinc,  but  also  by  cadmium,  aluminium  and  magnesium, 
and  to  some  extent  by  iron  pyrites,  arsenical  pyrites  and  several 
other  minerals ;  but  it  is  not  produced  by  tin,  lead  or  thallium.  .  The 
presence  of  zinc,  in  bodies,  is  best  detected  by  fusing  the  substance, 
in  powder,  with  two  or  three  parts  of  carb.  soda,  and  a  little  borax 
on  a  clean  piece  of  charcoal.  A  characteristic  ring-deposit  (lemon- 
yellow  and  phosphorescent,  hot ;  white,  cold ;  and  green,  on  cooling, 
after  ignition  with  cobalt  solution)  is  readily  obtained  as  a  rule  by 
this  treatment.  In  the  case  of  silicates  (and  indeed  in  all  cases)  the 
deposition  of  this  ring-coating  is  facilitated  by  first  fusing  the  test- 
substance  with  phosphor-salt,  and  then  crushing  the  saturated  bead 
on  the  anvil,  and  re-melting  it  with  carb.  soda  on  charcoal. 

(27)  Tin. — Native  tin  is  of  doubtful  occurrence.  The  metal  of 
commerce  is  obtained  entirely  from  the  binoxide,  known  in  its 
natural  occurrence  as  cassiterite  or  tinstone.  Tin  occurs  also,  but 
rarely,  as  a  sulphide  in  tin  pyrites ;  and  the  binoxide  is  present  in 
small  quantities  in  tantalates  generally,  and  in  certain  titaniates,  sili- 
cates and  other  compounds.  Metallic  tin  melts  easily,  without  colour- 
ing the  flame.  Before  the  outer  flame  it  rapidly  oxidizes  and  gives  off 
slight  fumes,  which  form  a  coating  on  the  fused  globule  and  on  the 
charcoal  immediately  around  the  latter.  The  coating  is  slightly- 
yellowish  whilst  hot,  and  white  or  greyish-white  when  cold,  and  it  is 
not  driven  off  by  the  flame,  but  ill  a  long  continued  blast  it  may 
become  reduced.  When  moistened  with  a  drop  of  cobalt  solution 

*  I  have  tried,  but  without  success,  to  make  this  reaction  available  for  the  detection  of 
phosphates  by  fusing  these,  in  powder,  with  boracic  acid,  borax  and  other  reagents,  and  then 
adding  a  piece  of  metallic  zinc  to  the  glass.  The  reaction,  although  sometimes  produced  by 
this  treatment,  is  too  uncertain  to  serve  as  a  test, 


40  BLOWPIPE    PRACTICE. 

and  ignited,  it  becomes  on  cooling  blueish-green.  SnO  and 
(neither  of  any  interest,  mineralogically)  burn  on  ignition,  and 
become  converted  into  binoxide.  The  latter  SnO,  is  infusible  by 
the  blowpipe,  but  on  charcoal,  in  a  well-sustained  blast,  it  is  reduced 
to  metal.  The  reduction  is  greatly  facilitated  by  the  addition  of  carb. 
soda,  neutral  oxalate  of  potash,  or  a  mixture  of  carb.  soda  and  cyanide 
of  potassium,  the  latter  acting  most  rapidly.  In  borax,  the  binoxide 
is  very  slowly  attacked  and  dissolved;  and  phosphor-salt  acts  upon  it 
still  more  slowly.  With  both  reagents  the  glass  remains  clear  when 
flamed.  With  soda  in  the  outer  flame,  it  forms,  with  effervescence,  a 
greyish- white  infusible  mass.  In  a  good  reducing  flame  (especially  if 
a  little  borax  be  added  to  promote  fusibility)  it  yields  reduced  metal. 
As  pointed  out  by  Berzelius,  a  small  portion  of  borax  should  always 
be  added  to  the  soda  in  the  examination  of  tantalates  and  infusible 
bodies,  generally,  for  the  presence  of  tin.  A  malleable,  easily  oxidizable, 
metallic  globule  is  then,  as  a  rule,  obtained  without  difficulty;  but  when 
a  trace  only,  or  very  small  percentage  of  tin  is  present,  the  regular 
reducing  process  (explained  on  page  17)  must  be  resorted  to.  A 
button  of  metallic  tin  may  be  distinguished  by  its  malleability,  feeble 
sublimate  and  ready  oxidation,  from  other  metallic  globules  as 
obtained  by  the  blowpipe.  In  nitric  acid  it  becomes  converted  into 
a  white  insoluble  powder  (SnO2),  behaving  in  this  respect  like  anti- 
mony ;  but  the  latter  metal  gives  a  brittle  button,  and  also  a  copious 
sublimate  or  ring-deposit  which  volatilizes  wholly  or  in  chief  part, 
and  communicates  to  the  flame  a  greenish  coloration.  From  silver, 
the  tin  globule  is  distinguished  by  its  ready  oxidation,  and  its  con- 
version into  insoluble  binoxide  by  nitric  acid — silver,  in  that  reagent, 
dissolving  rapidly.  From  lead  and  bismuth,  it  is  distinguished  also 
by  this  acid  reaction,  and  by  the  non-formation  on  charcoal  of  a 
yellow  sublimate.  When  small  pieces  of  tin  and  lead  (or  tin  and 
thallium,  or  tin  and  bismuth),  are  melted  together,  a  remarkable 
oxidation  ensues — the  fused  mass  becoming  rapidly  encrusted,  and 
continuing,  after  withdrawal  from  the  flame,  to  push  out  excrescences 
of  white  and  yellow  oxides.  (See  Appendix,  No.  21). 

IV. FLUX-COLOURING    METALS. 

The  oxides  of  the  metals  of  this  group  possess,  in  common,  the 
property  of  communicating  distinct  and  more  or  less  characteristic 


REACTIONS. 


41 


colours  to  borax  and  phosphor-salt  glasses  before  the  blowpipe.  By 
some,  also,  a  colour  is  imparted  to  the  soda  bead ;  but  most  of  these 
oxides  are  insoluble  in  carb.  soda.  They  fall  into  two  leading  sections, 
as  in  the  following  arrangement : 


B. — Not  reducible  from  an  oxidized 
or  other  condition  by  the  blowpipe. 

Bl. — The  borax-glass  not  rendered 
opaque  by  naming : 

Manganese.  Chromium.  Vana- 
dium. 

B2. — The  borax-glass  converted  by 
flaming  into  a  dark  or  light  enamel : 

Uranium.     Cerium.     Titanium. 


A. — "Reducible  from  an  oxidized  or 
other  condition  by  the  blowpipe. 

A1.  — Fusible,  and  therefore  obtained 
by  reduction  in  metallic  globules : 

Copper. 

A2.  —  Infusible  (practically),  and 
therefore  obtained  by  reduction  in  the 
form  of  separate  grains  or  scales : 

t  Magnetic : 

Nickel.     Cobalt.     Iron. 

ft  Non-magnetic : 

Tungstenuin.     Molybdenum. 


(28)  Copper. — This  metal  occurs  frequently  in  the  native  state. 
Also  as  a  base  in  numerous  sulphides,  and  in  certain  arsenides, 
selenides,  sulpharsenites  and  sulphantimonites.  In  combination  like- 
wise with  chlorine.  Also  in  an  oxidized  condition  as  Cu20  and  CuO  ; 
and  in  the  latter  form,  as  a  base,  very  commonly  in  arseniates,  phos- 
phates and  carbonates;  and  less  commonly  as  a  sulphate,  chromate, 
vanadiate  and  silicate.  Metallic  copper,  on  charcoal,  melts  before  the 
blowpipe  into  a  malleable  globule,  the  surface  of  which,  if  exposed  to 
the  outer  flame,  becomes  quickly  tarnished  by  a  black  coating  of 
oxide.  This  oxide  imparts  to  the  flame-border  a  rich  green  colour. 
Cupreous  sulphides,  arsenides  and  related  compounds  bepome  con- 
verted by  careful  roasting,  with  avoidance  of  fusion  (see  the  Opera- 
tion, page  11),  into  the  same  black  oxide;  and  a  roasting  of  this 
kind  is  always  necessary  as  a  preliminary  to  the  reduction  of  the  cop- 
per, and  its  detection  by  fusion  with  borax.  Both  the  red  and  black 
oxides  fuse  readily  and  become  reduced  on  charcoal.  With  borax 
and  phosphor-salt,  the  glass  after  exposure  to  an  oxidating  flame, 
is  green  whilst  hot,  and  clear-blue  when  quite  cold — unless  much 
iron  or  nickel  be  present,  in  which  case  it  retains  its  green  colour 
on  cooling.  In  a  reducing  flame,  especially  on  charcoal,  the  glass 
becomes  almost  colourless,  and  on  cooling  turns  brick-red  and 
opaque.  This  reaction  (which  serves  for  the  detection  of  copper  in 
the  presence  of  most  other  flux-colouring  bodies)  is  developed  more 


42  BLOWPIPE    PRACTICE. 

easily  with  borax  than  with  phosphor-salt,  but  when  very  little 
copper  oxide  is  present  in  the  glass,  it  is  not  always  obtained  without 
long  blowing.  If,  however,  a  small  piece  of  tin  or  iron-wire  be  stuck 
through  the  soft  glass,  and  the  bead  be  then  again  submitted  for  a 
few  moments  to  a  reducing  flame,  the  opaque  red  glass  (due  to  the 
reduction  of  the  CuO  to  Cu20)  is  readily  produced.  In  place  of  iron- 
wire,  a  small  fragment  of  any  substance  containing  FeO  (as  iron- 
vitriol,  magnetic  iron  ore,  spathic  iron,  &c.)  may  be  used  to  promote 
the  reduction,  the  FeO  becoming  converted  into  Fe203  at  the  expense 
of  some  of  the  oxygen  of  the  copper  compound.  The  fusion  may 
then  be  performed  on  platinum  wire ;  but,  in  any  case,  the  bead 
m.ust  not  be  kept  too  long  in  the  flame,  as  the  whole  of  the  copper- 
oxide  might  be  reduced  to  metal,  and  the  glass  become  colourless  by 
prolonged  fusion.  By  this  reaction,  the  presence  of  copper  in  bodies 
generally  (after  the  preliminary  roasting  of  those  which  contain 
sulphur,  antimony,  &c.)  is  unmistakably  revealed.  Another  charac- 
teristic reaction  is  the  bright  azure-flame  produced  by  chloride  of 
copper.  The  slightly-roasted  substance  may  be  moistened  with  a 
drop  of  hydrochloric  acid — or  fused  with  chloride  of  silver — and 
held  just  within  the  point  of  an  oxidating  flame.  If  copper  be  pre- 
sent, the  flame  around  the  test-substance  will  exhibit  a  brilliant 
azure  coloration.  The  test  may  also  be  made  by  simply  fusing  the 
substance  on  platinum  wire  with  phosphor-salt,  and  then  adding 
some  chloride  of  sodium  to  the  bead.  (See,  also,  Appendix,  No.  12). 

(29)  Nickel. — Occurs  in  small  and  variable  proportions  in  most 
examples  of  meteoric  iron,  and  also  in  some  meteoric  stones  as  a 
phosphide  and  sulphide.  In  minerals  proper,  it  is  found  more 
especially  as  an  arsenide,  antimonide,  sulphide  and  sulpharsenite. 
It  occurs  also  in  an  oxidized  condition,  at  times  as  a  simple  oxide 
in  coatings  on  nickel  ores,  but  more  commonly  as  an  arseniate,  car- 
bonate, sulphate  and  silicate.  In  some  (mostly  magnesian)  silicates, 
and  in  the  apple-green  variety  of  calcedony,  known  as  chrysoprase, 
it  is  present  in  minute  quantity  as  the  colouring  material  of  the 
substance.  Metallic  nickel  is  infusible  in  the  blowpipe  flame.  As 
obtained  by  reduction  of  the  oxide  NiO  by  carb.  soda  or  other 
reducing  agent  on  charcoal,  it  forms  numerous  minute  particles  of  a 
shining  white  colour.  These  are  strongly  magnetic.  Sulphides, 


ABACTIONS.  43 

arsenides  and  related  compounds,  become  converted  by  roasting  into 
this  oxide.  The  latter  is  unaltered  per  se  by  the  blowpipe  flame. 
With  borax,  it  forms  in  the  O.F.  a  glass  which  is  amethystine  in 
colour  whilst  hot  (if  the  NiO  be  in  moderate  quantity),  and  pure 
brown  or  yellowish-brown  when  cold.  If  not  too  deeply  coloured, 
the  glass  on  the  addition  of  a  carbonate  or  other  salt  of  potash  in 
excess,  is  rendered  more  or  less  distinctly  blue  or  greyish-blue.  The 
reaction,  however,  is  not  very  strongly  marked,  and  except  under 
special  conditions  it  can  scarcely  be  regarded  as  characteristic.  In 
the  R.F.,  the  borax  glass  becomes  grey  and  opaque  on  cooling,  from 
precipitation  of  reduced  particles  of  metal.  This  is  the  characteristic 
blowpipe-reaction  of  nickel.  It  serves  for  the  detection  of  that 
metal  (when  occurring  in  more  than  a  very  small  percentage)  in  the 
presence  of  cobalt  and  iron  oxides,  but  it  is  masked  by  the  presence 
of  copper.  When  copper  and  nickel  occur  together,  however,  the 
presence  of  the  latter  may  be  suspected  by  the  borax  glass,  after 
exposure  to  an  oxidating  flame,  remaining  green  when  cold ;  whereas 
with  copper  oxide  alone,  it  becomes  clear  blue  on  cooling.  The 
reaction,  nevertheless,  is  merely  suggestive,  as  it  is  produced  by  other 
metals,  Fe,  Or,  &c.,  when  associated  with  copper.  With  phosphor- 
salt,  NiO  produces  much  the  same  reactions  as  with  borax,  only  the 
glass  in  the  oxidating  flame  is  less  distinctly  coloured.  With  carb. 
soda  on  charcoal,  as  stated  above,  it  is  reduced  to  minute  shining 
particles  of  magnetic  metal. 

(30)  Cobalt. — This  metal,  as  an  essential  constituent,  occurs  only 
in  a  small  number  of  minerals,  and  chiefly  as  an  arsenide  and  sul- 
phide, separately  and  combined.  More  rarely  it  is  found  as  a  selenide 
and  oxide,  and  occasionally  as  an  arseniate  ;  but  it  is  present  in 
traces,  as  an  accidental  component,  in  many  sulphides  and  arsenides, 
as  in  varieties  of  arsenical  pyrites,  cubical  pyrites,  &c.  The  metal 
itself  is  practically  infusible.  Sulphides,  arsenides,  &c.,  become  con- 
verted by  roasting  into  the  oxide  CoO.  This,  with  carb.  soda  on 
charcoal,  is  readily  reduced  to  shining,  magnetic  particles  of  metal. 
With  both  borax  and  phosphor-salt,  and  in  both  flames,  the  oxide 
forms  glasses  of  a  deep  blue  colour,  even  when  present  in  traces  only. 
This  is  the  characteristic  reaction.  When  much  iron,  nickel,  or 
copper  is  present,  the  glass  however  is  dark  green ;  but  copper  and 


44  BLOWPIPE    PRACTICE. 

nickel  may  be  removed  by  reduction  in  the  inner  flame  (especially  if 
a  small  piece  of  tin  be  added  to  the  glass  on  charcoal),  and  the  tint 
derived  from  iron  is  generally  overpowered  in  the  outer  flame  by  the 
much  stronger  reaction  of  the  cobalt. 

(31)  Iron. — Occurs  in  the  simple  state  in  meteoric  iron,  though 
commonly  alloyed  with  a  small  percentage  of  nickel.  Occurs  also, 
and  in  numerous  localities,  in  various  sulphides,  arsenides  and  sul- 
phur-salts ;  and  in  an  oxidized  condition  as  FeO  +  Fe2O3  in  magnetic 
iron  ore,  as  Fe203  in  haematite,  &c. ;  and  as  FeO  or  Fe2O3  in  numerous 
silicates  and  other  oxygen  salts.  Metallic  iron  is  practically  infusible 
in  the  blowpipe-flame,  but  the  extremity  of  a  very  thin  wire  may  be 
oxidized  and  then  fused.  Hard  wires  fuse  in  general  the  most  easily, 
and  the  fusion  is  accompanied  by  a  rapid  scintillation  or  emission  of 
sparks,  whilst  very  frequently  a  thin  green  flame  streams  from  the 
point  of  the  wire.  The  latter  reaction  is  due  to  the  presence  of 
phosphorus.  (See  Appendix,  No.  11.)  Sulphides,  arsenides,  &c., 
become  converted  into  the  sesquioxide  Fe203  (often  termed  "red 
oxide")  by  roasting.  This  oxide,  by  fusion  with  carb.  soda  and  a 
little  borax  on  charcoal,  is  easily  reduced  to  shining  particles  of 
metal,  strongly  attractable  by  the  magnet.  On  platinum  wire  or 
other  non-reducing  support,  it  forms  with  soda  a  slaggy  infusible 
mass.  It  dissolves  readily,  on  the  other  hand,  in  borax  and  phos- 
phor-salt, forming  glasses  which  are  reddish  or  yellowish  whilst  hot, 
and  very  pale-yellow  or  almost  colourless  when  cold,  after  exposure 
to  the  OF ;  and  more  or  less  of  a  bottle-green  colour  after  treatment 
in  the  R.  F.,  especially  if  a  small  piece  of  tin  be  added  to  promote 
reduction,  Fe2O3  becoming  thus  converted  into  FeO.  All  minerals 
which  contain  5  or  more  per  cent,  of  iron  become  magnetic  after 
ignition  or  fusion.  By  this  reaction,  ferruginous  substances  may  be 
easily  recognized,  as  although  cobaltic  and  nickeliferous  bodies  also 
become  more  or  less  magnetic  on  ignition,  these  latter  bodies  are  of 
rare  occurrence.  They  are  readily  distinguished,  moreover,  from 
ferruginous  substances  by  the  colours,  &c.,  of  the  glasses  which  they 
form  with  borax.  When  the  presence  of  iron  has  been  recognized  in 
a  silicate  or  other  body,  it  is  often  desirable  to  ascertain  whether  the 
iron  is  present  as  sesquioxide  Fe'^03,  or  partly  or  wholly  as  protoxide, 
FeO.  This  may  be  determined  by  adding  some  of  the  test-substance, 


REACTIONS.  45 

in  powder,  to  a  bead  of  borax  coloured  blue  by  previous  fusion  with 
a  few  particles  of  oxide  of  copper,  and  exposing  the  bead  (in  a  loop 
of  platinum  wire)  to  the  point  of  the  blue  flame  until  the  substance 
begins  to  dissolve.  If  any  FeO  be  in  the  substance,  it  will  become 
converted  into  Fe2O3  at  the  expense  of  some  of  the  oxygen  of  the 
copper  oxide,  and  the  latter  will  thus  become  reduced  to  suboxide^ 
Cu20,  causing  red  streaks  and  spots  to  appear  in  the  glass,  as  this 
cools.  If  no  FeO  be  present,  the  glass  will,  of  course,  become  green 
on  cooling,  but  will  remain  transparent.  (See  Appendix,  No.  5.) 
A  very  minute  trace  of  iron  may  be  detected  by  the  following 
process :  Fuse  into  a  bead  of  phosphor-salt,  on  platinum  wire,  as 
much  of  the  substance,  in  powder,  as  the  bead  will  take  up.  Then 
saturate  the  bead  with  successive  portions  of  bisulphate  of  potash  (or 
treat  the. crushed  bead  with  that  reagent  in  a  platinum  spoon),  and 
dissolve  out  the  soluble  matters  in  warm  water.  Finally,  place  in 
the  solution  a  very  small  particle  of  ferrocyanide  of  potassium 
("yellow  prussiate").  If  iron  be  present,  a  deep-blue  precipitate 
will  necessarily  ensue. 

(32)  Tungstenum  or  Wolframium. — This  comparatively  rare  metal 
is  known  in  nature  only  in  an  oxidized  condition,  as  WO3,  a  compound 
which  occurs  occasionally  alone,  but  more  commonly  in  combination 
with  bases,  thus  forming  the  small  group  of  timgstates.  Tungstic 
acid  or  anhydride  WO3,  is  scarcely  affected  by  the  blowpipe-flame ; 
but  on  charcoal,  after  long  ignition  in  the  R.  F.,  it  becomes  blackened, 
by  conversion  into  W2OS.  With  carb.  soda  or  neutral  oxalate  of 
potash,  it  is  reduced  on  charcoal  to  minute  particles  of  metallic 
timgstenum ;  but  if  much  soda  be  used,  the  portion  of  test-matter 
absorbed  by  the  charcoal  is  generally  obtained  (by  washing  in  the 
agate  mortar,  page  17)  in  the  form  of  minute  yellow  specks,  .of 
metallic  lustre,  consisting  of  a  compound  of  soda  and  ttmgstic  oxide. 
On  platinum  wire,  with  carb.  soda,  it  dissolves  more  or  less  readily 
into  a  yellowish  glass,  which  becomes  opaque  and  somewhat  crystal- 
line on  cooling.  Borax  dissolves  it  readily.  After  exposure  to  the 
O.  F.  the  glass  is  yellowish  and  clear,  but  becomes-  enamelled  by 
flaming.  In  the  R.  F.,  with  excess  of  test-matter,  the  glass  is 
yellowish-brown,  and  by  flaming  or  on  cooling  it  becomes  opaque. 
With  phosphor-salt,  in  a  reducing  flame,  a  deeply  coloured  greenish- 


46  BLOWPIPE    PRACTICE. 

blue  glass  is  obtained.  This  is  the  characteristic  blowpipe  reaction 
of  tungstenum  compounds ;  but  if  much  iron  be  present,  the  glass 
becomes  deep-red.  The  presence  of  tungstenum  may  also  be  detected 
by  fusing  the  powdered  test-substance  with  3  or  4  parts  of  carb,  soda 
and  a  little  nitre  in  a  platinum  spoon  or  loop  of  thick  platinum-wire, 
dissolving  out  the  soluble  alkaline  tungstate  (as  explained  on  page  20), 
decanting  the  clear  solution,  acidifying  it  with  a  few  drops  of  hydro- 
chloric acid,  and  placing  in  it  a  piece  of  zinc.  A  dark-blue  coloration 
(from  reduction  of  the  WO3  to  W2O3)  will  rapidly  result. 

(33)  Molybdenum. — This  metal  occurs  in  nature  most  commonly 
in  combination  with  sulphur,  in  the  sulphide  molybdenite,  a  mineral 
which  presents  a  curious  resemblance  to  graphite  in  many  of  its  pro- 
perties (foliated  or  scaly-granular  texture,  softness  and  flexibility, 
soapy  feel,  detonation  with  nitre,  infusibility,  &c.).  It  occurs  also, 
though  rarely,  in  an  oxidized  condition  as  MoO3,  this  latter  compound 
being  found  at  times  alone,  but  more  commonly  combined  with  lead 
oxide  in  the  molybdate  wulfenite.  Molybdic  acid  or  anhydride, 
MoO3,  melts  easily  on  charcoal,  tinges  the  flame  yellowish-green,  and 
becomes  gradually  volatilized,  forming  a  deposit  which  is  slightly 
yellowish  whilst  hot,  and  white  when  cold.  When  touched  by  the 
reducing  flame,  this  deposit  assumes  a  dark-bluish  tinge  from  partial 
conversion  into  Mo203.  In  addition  to  the  white  coating,  an  indis- 
tinct reddish  deposit  is  also  formed  near  the  test-matter.  With  carb. 
soda,  reduction  to  minute  steel-grey  particles  is  easily  effected  on 
charcoal.  On  platinum  wire,  solution  takes  place  with  effervescence. 
With  borax,before  the  0.  F.,  a  yellowish  glass,  which  becomes  grey 
and  opaque  by  flaming,  is  formed ;  and  in  the  R.  F.,  a  brown  or  grey 
glass,  with  separation  of  dark  flecks,  the  latter  best  seen  by  pressing 
tjie  bead  flat  before  it  cools.  With  phosphor-salt,  on  cooling,  and 
especially  after  exposure  to  a  reducing  flame,  a  fine  green  glass 
results.  By  this  reaction  (combined  with  the  property  of  colouring 
the  flame  pale  yellowish-green,*  and  yielding  per  se  or  with  carb.  soda 
a  white  sublimate  and  reduced  particles  of  non-magnetic  metal), 
molybdenum  compounds  are  chiefly  recognized  in  blowpipe  practice. 
Molybdic  acid  and  molybdates,  as  first  made  known  by  Von  Kobell, 

*  Although  molybdenum  compounds  colour  the  Bunsen  flame  very  distinctly,  they  give  no 
coloured  bands  iu  the  spectroscope,  but  merely  o  continuous  spectrum. 


REACTIONS*  47 

when  warmed  with  sulphuric  acid,  produce  a  rich  blue  solution  on 
the  addition  of  alcohol.  If  the  test-substance  be  fused  with  carb.  soda 
and  nitre,  and  the  solution  of  the  alkaline  molybdate  be  treated  with 
hydrochloric  acid  and  metallic  zinc,  a  bluish  colour  may  appear  at  first, 
but  this  quickly  changes  to  dark-brown.  (See  under  Tungstenum, 
No.  32,  above.) 

(34)  Manganese. — -Does  not  occur,  in  nature,  in  the  metallic  state. 
Occurs  occasionally  as  an  arsenide  and  sulphide,  but  is  chiefly  found 
in  an  oxidized  condition — mostly  as  MnO2  and  Mn203  (these  com- 
pounds occurring  alone,  combined  together,  or  as  hydrates) ;  and  as 
MnO  in  various  silicates,  carbonates,  phosphates,  tungstates,  &c. 
As  an  accidental  or  inessential  component  it  is  present  in  the  latter 
state  in  very  numerous  minerals.  In  these,  the  MnO  generally 
replaces  small  portions  of  MgO,  CaO,  or  FeO.  Manganese  oxides 
are  not  reduced  by  carb.  soda  on  charcoal.  Yery  little  of  the  oxide 
dissolves  in  the  flux,  but  this  communicates  to  the  bead  a  green 
colour  whilst  hot,  and  a  blue  or  greenish-blue  colour  when  cold. 
The  reaction  is  brought  out  more  prominently  by  the  addition  of  a 
little  borax  to  the  soda,  as  this  promotes  solution  (see  Appendix,  No. 
9) ;  and  it  is  also  increased  in  intensity  by  melting  a  small  portion 
of  nitre  into  the  bead,  or  by  pressing  the  hot  bead  upon  a  small 
fragment  of  nitre.  A  greenish-blue  bead  of  this  kind  is  known 
technically  as  a  "turquoise  enamel."  Manganese  oxides  dissolve 
readily  in  borax  and  in  phosphor-salt,  and  the  solution  in  the  case  of 
the  higher  oxides  (MnO2  especially)  is  accompanied  by  great  effer- 
vescence or  ebullition,  due  to  the  escape  of  oxygen  from  the  test- 
matter.  Oxygen  is  also  evolved  when  these  oxides  are  strongly 
ignited  per  &e,  as  in  a  closed  tube,  &c.  (See  under  "Oxygen,"  above.) 
The  borax  glass  after  exposure  to  an  oxidating  flame  presents  a 
beautiful  amethystine  colour.  In  a  reducing  flame  it  becomes  colour- 
less, but  if  allowed  to  cool  slowly  it  absorbs  oxygen,  and  the  ame- 
thystine or  violet  colour  is  restored.  This  may  be  prevented  by 
urging  a  stream  of  air  from  the  blowpipe  upon  the  bead,  directly  the 
latter  is  removed  from  the  flame.  When  very  little  manganese  is 
present  in  the  test-matter,  the  formation  of  a  violet-coloured  glass  is 
facilitated  by  the  use  of  a  small  fragment  of  nitre.  The  phosphor- 
salt  glasses  resemble  those  produced  with  borax,  only  the  amethystine 


48  BLOWPIPE    PRACTICE. 

colour  is  paler,  and  when  very  little  manganese  is  present  it  is  scarcely 
developed  without  the  aid  of  nitre.  The  great  test  for  the  presence 
of  manganese  in  bodies,  is  the  formation  of  a  turquoise  enamel  by 
fusion  on  platinum  wire  or  foil  with  carb.  soda  and  a  little  borax. 
Less  than  one  part  in  a  thousand  may  be  easily  detected  by  this  re- 
action ;  and  by  the  addition  of  nitre,  as  described  above,  the  reaction 
becomes  still  more  delicate.  Chromium  compounds  when  fused  with 
carb.  soda  in  a  reducing  flame  form  a  yellowish-green  mass,  which 
might  in  some  cases  be  thought  to  arise  from  the  presence  of  man- 
ganese. But  if  a  greenish  mass  of  this  kind  be  fused  with  sufficient 
boracic  acid  or  silica  to  form  a  clear  glass,  the  latter  in  the  case  of 
manganese  will  present  an  amethystine  colour,  whilst  in  that  of 
chromium  it  will  be  emerald-green.  (See  Appendix,  No.  16.) 

(35)  Chromium. — Traces  of  this  metal  occur  in  some  varieties  of 
meteoric  iron,  but  otherwise  chromium  is  found  in  nature  only  in  an 
oxidized  condition,  as  Cr203  and  as  CrO3.  In  the  former  state  it 
occurs  occasionally  alone,  as  in  chrome  ochre;  but  more  commonly 
in  combination  with  iron  in  chromic  iron  ore,  or,  as  a  base,  in  certain 
silicates,  and  in  varieties  of  spinel.  In  many  silicates  it  is  present  as 
an  inessential  component,  as  in  the  emerald,  proper.  In  the  condition 
of  CrO3,  it  occurs  in  combination  with  lead  oxide  or  copper  oxide  in 
the  small  group  of  chromates.  The  leading  blowpipe  reactions  of 
chromic  oxide  are  as  follows :  Per  se,  the  oxide  is  practically  un- 
changed. With  carb.  soda,  it  dissolves  more  or  less  readily,  forming 
a  yellowish,  opaque  bead  in  the  outer  flame,  and  a  yellowish-green 
bead  in  a  reducing  flame.  If  a  particle  or  two  of  nitre  be  fused  into 
the  bead,  the  latter  becomes  blood-red  whilst  hot,  and  light-yellow 
when  cold — a  soluble  alkaline  chromate  resulting.  With  borax  and 
phosphor-salt,  clear,  emerald-green  glasses  are  produced,  especially  by 
treatment  in  a  reducing  flame,  and  after  complete  cooling.  Whilst 
hot,  the  glass  is  yellowish  or  red,  as  in  many  other  cases.  The  pro- 
duction of  an  emerald-green  glass  with  borax  generally  serves  for  the 
detection  of  chromium  compounds ;  but  the  character  becomes  neces- 
sarily masked  to  some  extent  by  the  presence  of  other  flux-colouring 
bodies,  as  iron,  copper,  and  cobalt  oxides,  for  example.  In  the 
presence  of  bodies  of  this  kind,  chromium  is  best  detected  by  fusing 
the  test-matter  (in  powder)  with  three  or  four  parts  of  carb.  soda, 


REACTIONS.  49 

and  a  little  nitre  in  a  platinum  spoon  or  loop  of  stout  platinum-wire. 
A  soluble  alkaline  chromate  then  results.  The  solution  (see  page  20), 
filtered  or  carefully  decanted  from  the  insoluble  residuum,  may  be 
divided  into  two  portions.  One  portion  may  be  evaporated  to  dry- 
ness,  and  the  resulting  deposit  tested  by  fusion  with  borax.  The 
other  portion  may  be  carefully  neutralized  by  a  drop  or  two  of  dilute 
nitric  acid,  or  acetic  acid,  and  tested  with  a  fragment  of  nitrate  of 
silver  :  a  red  precipitate  should  be  produced.  Chromates,  also,  when 
treated  with  sulphuric  acid  and  alcohol,  form  a  rich  green  solution 
which  remains  green  on  dilution.  Chromic  acid,  CrO,  per  se,  blackens 
when  ignited,  gives  off  oxygen,  and  becomes  converted  into  chromic 
oxide.  Bichromates,  and  many  chromates  also  (but  not  neutral 
alkaline  salts),  produce  the  same  reaction. 

(36)  Vanadium. — Occurs,  in  nature,  only  in  an  oxidized  condition, 
as  V2O5,  combined  with  lead-oxide,  and  more  rarely  with  other  bases, 
in  the  small  group  of  vanadates.     On  charcoal,  vanadic  acid,  fuses 
and  becomes  in  part  reduced  to  dark-grey  or  black  shining  scales  of 
suboxide.     If  heated  on  a  fragment  of  porcelain  or  other  non-reducing 
support,  it  fuses  without  decomposition,   and  congeals  with   vivid 
emission  of  light,  on  removal  from  the  flame,  into  a  red  or  dark 
orange-coloured   crystalline   mass.     With    borax,    it   forms   a   clear 
yellowish-green  glass,  and  with  phosphor-salt  a  yellow  glass,  on  cool- 
ing, after  exposure  to  the  outer  flame ;  and  emerald-green  glasses 
with  both  fluxes,  on   cooling,  after  exposure  to  a  reducing  flame. 
With  hydrochloric  acid  and  alcohol,  vanadates  give  a  green  solution 
which  becomes  light-blue  on  dilution  (Yon  Kobell).     In  addition  to 
this  test,  it  may  be  observed  that  whilst  chromium  compounds  give 
in  the  O.  F.  with  phosphor-salt  (on  cooling)  a  green  glass,  the  glass 
formed  by  vanadium  remains  yellow  when  cold — in  the  absence,  at 
least,  of  copper  or  other  flux-colouring  bodies. 

(37)  Uranium. —  Occurs  only  in  an  oxidized  condition  :  chiefly  as 
UO,  IPO3  in  the  mineral  pitchblende,   and  as  IPO3  in  uran  ochre 
and  a  few  comparatively  rare  phosphates,  sulphates,  carbonates,  and 
silicates.     The  sesquioxide  is  infusible  per  se,  but  is  blackened  in  the 
R.  F.  from  partial  reduction  to  UO.     It  is  insoluble  in  soda,  and  is 
not  reduced  to  metal  by  that  reagent,  but  it  is  readily  dissolved  by 
borax  and  phosphor-salt.      The  borax  glass  is   deep-yellow  in  the 

5 


50  BLOWPIPE    PRACTICE. 

O.  F.,  and  dingy  brownish-green,  when  cold,  after  subjection  to  a 
reducing  flame ;  and,  if  thoroughly  saturated,  it  may  be  rendered 
black  by  naming.  The  phosphor-salt  glasses  present  a  striking  con- 
trast, in  being  brightly  coloured  :  yellowish-green  in  the  O.  F.,  and 
clear  chrome-green  in  the  B,  F.,  especially  when  cold.  This  reaction 
serves  to  distinguish  uranium  compounds  from  those  of  chromium, 
&c. ;  but  in  the  presence  of  other  flux-colouring  bodies  uranium  is 
not  readily  detected. 

(38)  Cerium. — Occurs  in  only  a  few  comparatively  rare  minerals 
— chiefly  as  a  fluoride,  or  in  an  oxidized  condition  in  certain  silicates, 
phosphates,  &c.     On  ignition,  CeO  becomes  converted  into  yellow  or 
reddish  Ce2O3.     This  remains  unchanged.     With  carb.  soda,  on  char- 
coal, it  is  reduced  to  grey  CeO,  but  gives  no  metal.     With  borax  in 
the  O.  F.  a  reddish  or  yellowish  glass  is  obtained,  and  in  the  B.  F.  a 
colorless  glass.    Both  glasses  become  opaque  when  flamed,  if  tolerably 
saturated.     With  phosphor-salt,  the  glasses  on  cooling  are  colorless, 
but  they  are  not  rendered  opaque  by  flaming,  even  if  strongly  satu- 
rated.   As  a  rule,  the  presence  of  cerium  in  minerals  cannot  be  safely 
proved  by  the  blowpipe  alone. 

(39)  Titanium. — Occurs,  in  nature,  in  an  oxidized  condition  only 
— as  TiO2  in  three  separate  forms  (Rutile,  Octahedrite,  Brookite), 
und  combined  with  lime,  yttria,  zirconia,  &c.,  in  the  small  group  of 
titaniates.     In  this  condition  it  is  present  also  in  certain  silicates  ; 
and  as  Ti2O3  it   partly   replaces    Fe2O3   in    titaniferous   iron  ores, 
TiO2  becomes  yellowish  on  ignition,  but  remains  infusible,  and  re- 
assumes  its  white  colour  on  cooling.      Moistened  with  nitrate  of 
•cobalt,  and  ignited,  it  becomes  green  when  cold.     With  soda,  on 
•charcoal,  it  is  not  reduced  to  metal,  but  it  fuses  with  effervescence, 
•and  on  cooling  the  surface  of  the  bead  shoots  into  broad  crystalline 
facets  of  a  pearly-grey  colour.     With  borax,  it  forms  in  the  O.  F.  a 
yellowish  glass  which  loses  its  colour  on  cooling,  and  when  saturated 
becomes  on  cooling  or  by  flaming  milk-white  and  opaque.     In  the 
B.  F.,  the  glass,  moderately  saturated,  assumes  on  cooling  a  brownish- 
amethystine  colour,  and  with  more  of  the  test-matter  it  becomes 
blackish-blue  and    opaque    on    congealing.      When    flamed,   a    light 
greyish-blue  film  spreads  over  the  surface  of  the  bead.     The  dark- 
blue  tint  (Plattner  calls  it  "brown")  arises  from  Ti'O3;  the  light-blue 


REACTIONS. 

mirface-film  from  the  partial  oxidation  of  this 
phosphor-salt,  the  glass  in  the  O.  F.  is  colorless  or 
and  in  the  R.  F.,  on  cooling,  it  assumes  a  fine 
When  titanium  compounds  contain  iron,  however,  the  glass  is  deep 
red-brown  or  blood-red.  In  the  case  of  Menaccanite  or  Titaniferous 
Iron  Ore,  proper,  this  reaction  is  very  marked  ;  but  it  is  not  suf- 
ficiently definite  to  serve  for  the  detection  of  small  quantities  of 
titanium  in  ordinary  iron  ores.  In  these,  the  presence  of  titanium 
is  most  readily  detected  as  follows  : — Reduce  a  portion  of  the  ore  to 
as  fine  a  powder  as  possible ;  warm  this  with  hydrochloric  acid  in  a 
small  covered  beaker-glass  for  about  half-an-hour  on  a  sand-bath, 
keeping  the  acid  just  at  the  boiling-point ;  add  a  little  water,  and 
filter  from  the  insoluble  rock-matter,  <fec. ;  place  a  piece  of  metallic 
tin  in  the  filtrate,  and  boil  for  ten  or  fifteen  minutes.  Thus  treated, 
the  deep-yellow  solution  will  quickly  become  greenish  and  then  color- 
less, and  on  the  boiling  being  continued,  a  pink  tinge  will  appear 
and  gradually  deepen  into  a  distinct  amethystine  colour.  In  the 
absence  of  titanium,  the  solution  will  of  course  remain  colorless,  but 
the  boiling  must  not  be  discontinued  too  soon.  The  presence  of 
titanium  in  iron  ores,  <fec.,  may  also  be  detected  by  fusing  the  test- 
matter,  in  fine  powder,  with  six  or  eight  parts  of  bisulphate  of  potash 
(added  in  successive  portions)  in  a  platinum  spoon ;  treating  the 
fused  mass  with  a  very  small  quantity  of  warm  water ;  decanting  or 
filtering  from  insoluble  matters ;  adding  a  few  drops  of  nitric  acid, 
and  then  five  or  six  volumes  of  water ;  and,  finally,  boiling  for  ten  or 
twelve  minutes.  Titanic  acid,  if  present,  is  precipitated  in  the  form 
of  a  white  or  pale-yellowish  powder.  This  may  be  fused  with 
phosphor- salt,  in  a  reducing  flame,  for  the  production  of  a  characteristic 
amethystine  glass.  As  pointed  out  by  Gustav  Rose,  a  glass  of  this 
kind,  rendered  colorless  or  nearly  so  by  the  O.  F.,  and  then  slightly 
flamed,  becomes  opalescent  from  the  precipitation  of  numerous  crys- 
tals of  TiO2.  These  are  best  examined,  in  the  flattened  bead,  by  a 
microscope  with  object  glass  of  moderate  but  not  too  low  power. 

V. — EARTH    METALS. 

This  group  is  to  a  great  extent  conventional.  Tantalum  is  placed 
in  the  group,  because  in  a  scheme  of  this  kind  it  can  scarcely  be 
placed  elsewhere.  The  representatives  of  the  group  are  separated 
from  those  of  the  preceding  series  by  their  property  of  forming 


52  BLOWPIPE    PRACTICE. 

uncoloured  glasses  with  the  blowpipe  fluxes ;  and  from  those  of  the 
next  series  by  their  non-alkaline  character.  With  reference  purely  to 
blowpipe  characters,  it  would  perhaps  be  a  more  satisfactory  arrange- 
ment if  magnesium  were  also  referred  to  this  group,  the  other 
metals  of  Group  6  and  those  of  Group  7  being  placed  together  in  a 
single  group  under  the  name  of  F  lame-colour  ers.  Keeping,  however, 
to  the  present  distribution,  it  may  be  pointed  out  that  aluminum 
compounds  are  distinguished  from  those  of  the  associated  metals  by 
not  forming  an  opaque  glass  with  borax,  and  by  the  blue  colour 
assumed  after  ignition  with  nitrate  of  cobalt.  Compounds  of  the 
other  metals  belonging  to  the  group  are  of  comparatively  rare 
occurrence. 

(40)  Tantalum. — Occurs  only  in  an  oxidized  condition  as  tantalic 
acid  (Ta205)  commonly  associated  with  columbic  or  niobic  acid  (Nb205) 
and  combined  with  iron  oxide  and  other  bases,  in  a  few  minerals  of 
exceptional  occurrence.       Tantalic  acid  becomes  pale  yellowish  on 
ignition,    but   resumes   its   white    colour   011  cooling,   and  remains 
infusible.    After  treatment  with  cobalt-solution  it  becomes  pale  flesh- 
red.     "With   carb.  soda  it  dissolves   with  effervescence,   but  is  not 
reduced.       With    borax,    it   dissolves    easily,    the    saturated   glass 
becoming  opaque  on  cooling  or  by  flaming.     With  phosphor-salt  it 
forms  a  permanently  clear  bead.     Its  presence  in  minerals  cannot  be 
safely  detected  by  the  blowpipe  alone. 

(41)  Aluminum. — Occurs  in  nature  as  a  fluoride  (in  cryolite,  &c.), 
but  essentially  as  an  oxide,  APO3.       The  latter  compound  occurs 
alone  and  in  a  hydrated  condition  (corundum,  diaspore,  gibbsite) ; 
and  in  combination  with  magnesia  and  other  bases  as  the  electro- 
negative principle  of  the  small  group  of  aluminates.     It  occurs  also, 
and  more  frequently,  as  a  base,  in  various  silicates,  phosphates,  and 
sulphates.     Exceptionally,  also,  as  an  arseniate  ;  and  in  combination 
with  an  organic  acid  in  the  mineral  mellite.     Alumina  presents  the 
following  blowpipe  reactions :  (1)  Per  se,  it  is  infusible  and  unchanged. 
(2)  Moistened  with   nitrate  of  cobalt,  and   ignited,  it  assumes,  on 
cooling,  a  fine  blue  colour.    The  reaction  is  exhibited  by  all  aluminous 
silicates,  phosphates,  &c.,  which  are  free  from  iron  oxides  or  other 
strongly  coloured  bases  (Seepage  12.)     (3)  Alumina  is  not  attacked 
by  carb.   soda.     (4)   It  is  very  slowly  dissolved  by  borax  and  phos- 
phor-salt, forming  colorless,   permanently   clear  beads.       (5)  It  is 


REACTIONS.  53 

dissolved,  in  fine  powder,  by  fusion  in  a  platinum  spoon  with  five 
or  six  partsof  bisulphate  of  potash  (page  20).  The  aqueous  solution 
of  the  fused  mass  yields  a  white  precipitate  (soluble  in  caustic  potash) 
with  ammonia.  Silicates  resist  this  treatment,  but  in  fine  powder 
many  are  soluble  in  hydrochloric  acid,  and  nearly  all  may  be  ren- 
dered soluble  by  previous  fusion  with  a  mixture  of  carb.  soda  and 
borax.  The  solution  (with  slight  addition  of  nitric  acid)  must  be 
evaporated  slowly  to  dryness,  the  residuum  moistened  with  a  couple 
of  drops  of  hydrochloric  acid,  water  added,  and  the  clear  supernatant 
liquid  decanted  or  filtered  from  the  insoluble  silica.  If  the  precipitate 
formed  in  the  filtrate  by  ammonia  be  brown  in  colour,  it  must  be 
separated  and  boiled  with  caustic  potash.  This  will  take  up  any 
alumina  that  may  be  present,  leaving  Fe203  undissolved. 

(42)  (rlucinum,  or,  Beryllium. — Occurs  only  in  an  oxidized  con- 
dition, BeO,  as  a  base  in  a  small  number  of  silicates  (Phenakite, 
Beryl,    Euclase,    &c.),    and   in  a   single    alurninate    (Chrysoberyl). 
Glucina  is  infusible  per  se,  and   is  not   dissolved   by  carb.    soda. 
With  cobalt  solution  it  becomes  pale  bluish-grey;  with  borax  and 
phosphor-salt  it  dissolves  more  or  less  readily,  the  saturated  glass 
becoming  opaque  on  cooling  or  when  flamed.     When  glucina  is  com- 
bined with  other  bodies,  its  blowpipe  reactions  are  not  sufficient  for 
its  detection. 

(43)  Zirconium. — Occurs  only  oxidized,  as  ZrO2  in  combination 
with  silica  and  various  bases  in  a  small  number  of  minerals.     The 
zircon  (ZrO2,  SiO'2),  distinguished  chiefly  by  its  hardness,  high  sp. 
gr.    (=4-2-4'8),  Tetragonal  crystallization,  and  infusibility,   is  the 
only  representative   species   of  tolerably  common   occurrence.      Zir- 
conia  when  ignited,  glows  with  more  than  ordinary  brightness,  but 
remains  unfused.     After  treatment  with  cobalt  solution,  it  assumes 
a  dull  violet  tinge.     It  is  not  dissolved  by  carb.  soda,  but  dissolves 
freely  in  borax  and  phosphor-salt,  forming  a  colourless  glass  which  on 
saturation  becomes  opaque  on  cooling  or  by  flaming.     Zircon  and 
other  silicates  in  which  zirconia  is  present  become  decomposed  by 
fusion  in  tine  powder  with  carbonate   of  soda,  and  they  are  then 
soluble  or  partially  soluble  in  hydrochloric  acid.     The  dilute  solution, 
as  first  pointed  out  by  BRUSH,  imparts  an  orange-yellow  or  reddish- 
brown  colour  to  turmeric  paper,  seen  most  distinctly  as  the  paper 
dries. 


54  BLOWPIPE  PRACTICE. 

(44)  Yttrium. — This  rare  metal    (almost  always   associated    with 
Erbium)  occurs  in  the  mineral  of  Yttrocerite  as  a  fluoride;  but  in 
general  it  is  found  in  an  oxidized  condition  (YO)  as  a  base  in  cer- 
tain silicates,  titanates,  tantalates,  niobates  and  phosphates,  all  of 
more  or  less  exceptional   occurrence.       The   blowpipe   reactions  of 
yttria  agree  in  all  essential  respects  with   those  of  glucina.     It  is 
thus  infusible  per  se,  and  also  with  carb.  soda  ;  but  soluble  in  borax 
and  phosphor-salt,  the  saturated  glass  becoming  opaque  by  flaming 
or  on  cooling.     Practically,  its  presence  in  minerals  escapes  detection 
by  the  blowpipe. 

VI. ALKALINE    EARTH-METALS. 

This  group  includes  magnesium,  calcium,  strontium,  and  barium. 
The  two  first  by  the  insolubility  of  their  oxides  (before  the  blowpipe) 
in  carb.  soda,  are  allied  to  the  metals  of  the  preceding  group,  whilst 
the  general  solubility  of  strontium  and  barium  compounds  in  that 
reagent,  connects  the  latter  metals  with  those  of  Group  VTI.  The 
carbonates,  sulphates,  fluorides,  &c.,  of  all  the  representatives  of  the 
group,  react  alkaline  after  strong  ignition,  and  thus  restore  the  blue 
colour  of  reddened  litmus-paper ;  but  in  other  compounds  (silicates, 
&c.),  the  reaction  is  less  clearly  marked  or  is  not  observable.  All 
the  oxides  belonging  to  this  group  dissolve  freely  in  borax  and 
phosphor-salt,  forming  clear  glasses  which  on  saturation  become 
opaque  by  flaming  or  when  cold.  Magnesium  compounds  impart  no 
colour  to  the  flame ;  compounds  containing  calcium  and  strontium 
colour  the  flame  red  or  crimson,  and  barium  compounds  communicate 
to  it  an  apple-green  coloration. 

(45)  Magnesium— Occ\.\rs,  though  rarely,  as  a  chloride,  and  still  more 
rarely  as  a  fluoride  ;  very  abundantly,  on  the  other  hand,  as  an  oxide, 
magnesia,  MgO.     This  compound,  though  occuring  alone  in  Peiiclase, 
arid  as  a  hydrate  in  Brucite,  is  chiefly  met  with  as  a  base  in  various 
alumiriates,  silicates,  sulphates,  carbonates,  borates,  phosphates  and 
arseniates.      Magmsia  is  infusible  per  se,  and  insoluble  in  carb.  soda. 
After  ignition  with  nitrate  of  cobalt  it  assumes  on  cooling  a  pale  flesh - 
red  colour.     This  reaction  is  manifested  by  magnesium  carbonates, 
silicates,  &c.,  in  the  absence  of  iron  or  other  colouring  oxides,  but  in 
many  cases  it  is  not  very  distinct.     Magnesia  does  not  colour  the 
blowpipe-flame,  and  its  compounds,  when  ignited  in  a  Bunsen-burner, 
give  no  spectrum  bands.     With  borax  and  phosphor-salt  it  dissolves 


REACTIONS.  55 

very  readily,  the  saturated  glass  becoming  opaque  on  cooling  or  when 
flamed.  The  non-coloration  of  the  flame  and  the  reaction  with  nitrate 
of  cobalt  generally  serve  to  distinguish  magnesian  compounds,  except 
in  the  case  of  certain  silicates.  In  these,  and  in  other  doubtful  cases, 
the  test-substance,  in  fine  powder,  may  be  dissolved  in  a  small  quan- 
tity of  hydrochloric  acid  in  a  porcelain  capsule  over  the  spirit  lamp 
or  Bunsen  flame  ;  or,  if  insoluble  in  acids,  it  may  be  rendered  soluble 
by  previous  fusion  with  a  mixture  of  carb.  soda  and  borax.  The 
fusion  is  best  performed  in  a  paper  cylinder  (according  to  Plattner's 
method),  the  cylinder  being  made  and  filled  as  directed  in  the  case 
of  the  lead  cylinder  on.  page  32.  The  solution  is  then  to  be  diluted, 
a  drop  of  nitric  acid  added,  the  whole  evaporated  to  dryness  (to  sepa- 
rate silica),  the  residuum  re -moistened  with  hydrochloric  acid,  distilled 
water  added,  and  the  solution  filtered.  In  the  filtrate,  APO  and 
Fe2O3,  if  present,  are  thrown  down  by  ammonia  in  slight  excess ; 
lime  is  next  precipitated  by  oxalic  acid  or  oxalate  of  ammonia ;  and 
finally  the  magnesia  is  separated  by  some  dissolved  phosphor-salt. 
Care  of  course  must  be  taken  in  each  case  to  see  that  the  precipitation 
be  complete. 

(46)  Calcium. — Occurs  frequently  as  a  fluoride,  and  occasionally  as 
a  chloride  ;  but  principally  in  an  oxidized  condition  (CaO)  as  a  base  in 
silicates,  carbonates,  sulphates,  phosphates  and  other  oxygen-  com- 
pounds. Lime  glows  strongly  on  ignition,  and  imparts  to  the  flame- 
border  a  distinct  red  colour,  but  this  is  less  intense  than  the  crimson 
coloration  produced  by  strontium  and  lithium  compounds.  The 
characteristic  bands  in  its  spectrum  are  two  in  number — an  orange, 
red  band  (a  little  farther  from  the  sodium  line  than  the  orange 
strontium  band),  and  a  clear  green  band.*  This  flame  reaction  is 

*  In  these  examinations,  a  small,  direct-vision  spectroscope— such  as  Browning's  pocket 
spectroscope  with  attached  scale  and  extra  prism— will  be  found  most  suitable.  By  a  little 
practice,  the  student  will  readily  recognize  the  positions  of  the  red  and  orange  lines,  without 
the  assistancs  of  the  scale,  by  their  relative  distance  from  the  sodium  line.  A  small  fragment 
of  lepidolite  will  give  the  sodium  and  lithium  lines  very  distinctly.  Strontianite,  and  also 
celestine,  after  a  short  exposure  to  the  flame,  give  the  orange,  red,  and  blue  lines  characteristic 
of  strontium  ;  heavy  spar  and  witherite,  the  characteristic  barium  bands ;  and  fluor-spar, 
gypsum,  calcite,  &c.,  the  red  and  green  calcium  lines.  The  effect  is  heightened  by  moistening 
the  calcined  test-matter  with  a  drop  of  hydrochloric  acid,  but  as  regards  the  above  (and  various 
other)  minerals,  the  distinctive  lines  come  out  very  vividly  by  a  sufficiently  prolonged  ignition 
of  the  substance  per  se.  The  small  sharp-edged  fragment  is  conveniently  held  in  the  platinum- 
tipped  forceps,  and  these  can  be  fixed  at  the  proper  height  by  thrusting  their  opposite  ends 
across  the  stem  of  one  of  the  ordinary  wire  supports  used  in  spectroscope  examinations. 


56  BLOWPIPE    PRACTICE. 

given  by  carbonates  and  sulphates,  as  well  as  by  fluor  spar,  after 
prolonged  ignition  in  the  Bimseii  flame,  but  as  a  rule  it  is  best 
obtained  by  moistening  the  test-substance  with  hydrochloric  acid. 
Per  se,  lime  is  infusible.  It  is  not  dissolved  by  carb.  soda,  but  dis- 
solves readily  by  fusion  with  borax  and  phosphor-salt,  the  saturated 
glasses  becoming  opaque  by  flaming  or  on  cooling.  With  nitrate  of 
cobalt  a  dark-grey  coloration  is  obtained.  For  the  detection  of  lime 
in  silicates,  see  under  Magnesium,  No.  45. 

(47)  Strontium. — Occurs  only,  among  natural  compounds,  in  an 
oxidized  condition,  as  SrO,  combined  with  sulphuric  acid  and  with 
carbonic  acid ;  more  rarely  with  silica.     Both  the  sulphate  and  car- 
bonate become  caustic  on  ignition,  and  then  give  the  crimson  flame- 
coloration  and  other  reactions  of  pure  strontia, — dissolving,  like  the 
latter,  very  readily  and  completely  in  carbonate  of  soda,  a  character 
by  which  strontium  and  barium  compounds  (with  those  of  the  alkali 
metals  proper)  are  at  once  distinguished  from  other  alkaline  earths. 
With  borax  and  phosphor-salt  strontia  dissolves  freely,  the  colorless 
glass  becoming  opaque  (if  sufficiently  saturated)  on  cooling  or  when 
flamed.    After  ignition  with  nitrate  of  cobalt,  strontia  becomes  dark- 
grey  or  black.      In  the  strontium    spectrum  the  distinctive  lines 
comprise  (1)  a  broad  orange-red  line,  quite  close  to  the  sodium  line, 
(2),  a  group  of  several  crimson  lines,  and  (3)  a  single  blue  line.     A 
small  fragment  of  strontianite  or  celestine  shews  these  lines  very 
distinctly  after  a  short  exposure  to  the  edge  of  the  Bunsen  flame.     If 
a  strontium  compound  be  fused  on  platinum  wire  with  chloride  of 
barium,  the  crimson  flame -coloration  is  destroyed.     By  this  character 
— as  well  as  by  the  spectrum — strontium  compounds  are  readily 
distinguished  from  those  of  lithium.     (See  Appendix,  No.  4.) 

(48)  Barium.— Occurs  in  nature  in  an  oxidized  condition   only, 
and  chiefly  as  a  sulphate  and  carbonate,  more  rarely  as  a  silicate. 
Present  also  in  some  of  the  naturally-occurring  oxides  of  manganese. 
Baryta  dissolves  entirely  in  carb,  soda,  and  resembles  strontia  in  its 
other  blowpipe  reactions,  except  as    regards  the   coloration  of  the 
flame  and  the  reaction  with  nitrate  of  cobalt.     It  communicates  to 
the  flame-border  an  apple-green  or  yellowish-green  colour,  and  be- 
comes reddish-brown  after  treatment  with  the  cobalt  solution  (page 
12),  but  the  latter  reaction  is  of  little  moment.     The  spectrum  of 


REACTIONS.  57 

barium  compounds  is  essentially  characterized  by  a  group  of  green 
lines,  four  or  five  in  number,  of  which  two  are  especially  vivid  and 
distinct;  with  a  line  or  two,  often  ill-defined,  in  the  orange  and 
yellow,  and  one  or  two  more  or  less  indistinct  lines  near  the  commence- 
ment of  the  blue,  the  whole  at  nearly  equal  distances  apart.  The 
group  of  green  lines  is  the  characteristic  portion  of  the  spectrum.  In 
the  calcium  or  lime  spectrum  there  is  only  a  single  well-pronounced 
green  or  yellowish-green  line,  whilst  the  spectra  of  Sr,  Na,  Li,  and  K, 
show  no  green  lines.  See  also  Appendix,  Nos.  1  and  2. 

VII. ALKALI    METALS. 

This  group  includes  Lithium,  Sodium,  Potassium,  and  Ammonium. 
Compounds  of  these  alkali  metals  much  resemble  strontium  and 
barium  compounds  in  their  general  blowpipe  reactions.  They  impart 
a  colour  to  the  flame,  and  dissolve  readily,  by  fusion,  in  carb.  soda. 
The  flame  coloration  of  lithium  compounds  is  crimson  ;  of  sodium 
compounds,  yellow ;  of  potassium  compounds,  clear  violet ;  of  ammo- 
nium compounds,  pale  or  dull  green. 

(49)  Lithium. — This  metal  as  an  essential  mineral-component 
occurs  only  in  an  oxidized  condition  (Li'O)  in  a  few  silicates  and 
phosphates ;  but  in  minute  quantities  it  appears  to  be  widely  dis- 
tributed throughout  nature.  The  presence  of  lithia  in  most  corn- 
pounds  is  readily  detected  by  the  crimson  coloration  imparted  to  the 
blowpipe  flame  or  that  of  the  Bunsen  burner,  especially  on  pro- 
longed ignition.  When  lithia  is  merely  present,  however,  as  an 
accidental  or  inessential  constituent,  the  flame-coloration  is  best 
brought  out  by  moistening  the  test-matter  in  powder  with  a  drop  or 
two  of  hydrochloric  acid.  The  mixtures  of  bisulphate  of  potash  and 
fluor-spar,  or  gypsum  and  fluor-spar,  recommended  in  books  for  this 
purpose,  often  bring  out  by  themselves  a  vivid  red  coloration.  By 
fusion  with  chloride  of  barium,  the  intensity  of  the  lithium  flame  is 
increased,  whereas  by  this  treatment  the  red  flame  of  strontium  is 
destroyed  (see  Appendix,  No.  4).  The  spectrum  of  lithium  is  also 
exceedingly  characteristic.  It  consists  practically  of  a  single  crim- 
son line,  much  farther  from  the  sodium  line  than  the  characteristic 
orange-red  line  of  strontium,  or  the  red  calcium  line.  Most 
examples  of  lepidolite  give  the  lithium  and  sodium  lines  together. 


58  BLOWPIPE    PRACTICE. 

(50)  Sodium  or  Natrium. — Widely  distributed  as  a  chloride,  and 
occurring  also  as  a  fluoride.      Present  also  abundantly  in  an  oxidized 
condition  (Na2O)  in  various,  silicates,  sulphates,  and  carbonates,  and 
in  the  nitrate  soda- nitre.       Distinguished  very  readily  in  most  cases 
by  the  strong  yellow  coloration  which  its  compounds  impart  to  the 
Bunsen  and  blowpipe  flame.    Its  spectrum  consists  of  a  single  yellow 
line  (as  sesn  in  ordinary  spectroscopes)  corresponding  in  position  with 
the  line  (or  double  line)  D  of  the  solar  spectrum.     This  yellow  line 
is  exceedingly  characteristic  ;  and  its  very  constant  presence  in  spectra, 
generally,  serves  as  a  convenient  index  to  the  position  of  other  lines, 
as  those  of  calcium,  strontium,  &c.     The  yellow  flame-coloration  is 
completely  hidden  if  viewed  through  a  deep-blue  glass. 

(51)  Potassium  or  Kalium. — Occurs  as  a  chloride ;  but  more  com- 
monly in  an  oxidized  condition  (K20)  as  a  sulphate  and  nitrate,  and  in 
various  (chiefly  aluminous)  silicates.     Potash  (if  perfectly  free  from 
soda)  imparts  to  the  outer  flame  a  clear  violet  tint,  but  this  coloration 
is  masked  or  rendered  more  or  less  invisible  by  the  least  trace  of  soda 
or  of  any  sodium  compound,  and  also  as  a  rule  by  other  flame-colouring 
bodies.     If  the  flame  bs  viewed  however,  as  first  shewn  by  Cartmell, 
through  a  deep-blue  glass  or  a  solution  of  indigo,  the  yellow  coloration 
due  to  sodium  becomes  entirely  obliterated,  and   the  potash-flame 
exhibits  a  bluish-red  colour.       The  indigo-solution  (1   part  indigo, 
8  concentrated  sulphuric  acid,  1500  water)  is  best  contained  in  a 
prism-shaped  or  wedge-shaped  bottle,  so  that  different  thicknesses 
may    be    conveniently    brought    between    the    eye    and    the    flame. 
Cornwall  has  recommended  a  solution  of  permanganate  of  potash  in 
place  of  the  indigo  solution.      When  the  potash  flame  is  obscured  by 
lithium,  it  will  be  rendered  visible,   according  to  Merz,  if  viewed 
through  a  green  glass,  the  lithium  flame  becoming  then  obliterated. 
A  good  deal  depends,  however,  011  the  shade  of  colour  of  these  glasses 
and  solutions,  and  the  results  are  not  always  entirely  satisfactory. 
Whenever  therefore  recourse  can  be  had   to  the  spectroscope,   the 
latter  should  always  be  employed.     The  potassium  spectrum  consists 
essentially  of  two  lines,  far  apart — a  red  line,  almost  at  the  commence- 
ment of  the  normal  spectrum  (it  coincides,  practically,  with  the  solar 
line  A),  and  a  violet  line  near  the  other  extremity  of  the  spectrum 
proper.    The  latter  line,  however,  is  not  generally  visible,  and  in  small 
spectroscopes  the  two  lines  can  rarely  be  seen  together.     The  red 


REACTIONS.  59 

line  is  the  characteristic  one.  It  lies  about  (but  not  quite)  as  far 
from  the  red  lithium-line  as  this  lies  f<*om  the  sodium-line.  Starting 
therefore  from  the  latter,  the  characteristic  orange  and  red  spectrum 
lines  of  the  common  alkaline  and  earthy  bodies  succeed  each  other  in 
the  following  order  :  (Na) — Sr — Oa — Sr  (group  of  lines) — Li — K  : 
one  of  the  red  Sr-lines  coinciding  with  the  solitary  Li-line.*  If  the 
student  be  uncertain,  at  any  time,  as  regards  the  red  K-line,  he 
should  insert  into  the  edge  of  the  Bunsen  flame  a  small  scale  of 
lepidolite  (or  other  lithium- containing  body),  when  the  relative  posi- 
tions of  the  two  will  at  once  become  apparent ;  or,  if  his  spectroscope 
be  fitted  with  an  extra  prism,  he  can,  of  course,  examine  the  two 
spectra  separately.  The  nitrate,  and  the  natural  sulphates  and 
chlorides  (as  well  as  the  ordinary  potassic  salts  of  the  laboratory, 
phosphates,  bromides.  &c.),  give  the  reaction  very  distinctly,  but  it  is 
not  always  produced  directly  by  natural  silicates.  To  detect  potash 
in  the  latter,  a  small  portion  of  the  silicate,  in  fine  powder,  must  be 
fused  on  a  loop  of  stout  platinum  wire  with  a  mixture  of  carb.  soda 
and  borax,  and  the  fused  bead  (crushed  to  powder)  must  be  boiled 
with  a  few  drops  of  hydrochloric  acid.  The  solution,  evaporated 
nearly  to  dryness,  or  a  small  portion  of  the  pasty  mass,  may  then  be 
examined  by  the  spectroscope.  The  presence  of  sodium  does  not 
interfere  with  the  production  of  the  red  potassium-line,  but  the 
supporting  wire  should  be  kept,  as  a  rule,  just  at  the  edge  of  the 
Bunsen-flame,  and  the  observations  should  be  made  in  a  darkened 
room. 

(52)  Ammonium. — Occurs  in  Inorganic  Nature  chiefly  as  a 
chloride ;  more  rarely  in  an  oxidized  condition  as,  a  sulphate  and 
borate.  Accidentally  present  also  in  many  bog  iron  ores  and  other 
minerals  which  contain  traces  of  intermixed  organic  matter.  Its 
presence  is  recognized  more  or  less  readily  by  the  odour  evolved  on 
moderate  ignition,  especially  if  the  substance,  mixed  with  dry  carb. 
soda,  be  ignited  in  a  test-tube.  A  slip  of  red  litmus-paper,  slightly 
moistened  and  placed  at  the  top  of  the  tube,  will  be  rendered  blue  by 
the  evolved  vapours  ;  and  these  will  also  manifest  themselves  in  white 
fumes  if  a  glass  rod  moistened  with  hydrochloric  acid  be  brought 


*  The  ash  of  a  cigar  or  of  ordinary  tobacco,  if  moistened  with  hydrochloric  acid,  will  show 
the  green  and  red  calcium  lines  and  the  red  K-line  very  distinctly.  The  lithium-line  is  also 
shewn  by  some  kinds  of  tobacco. 


60  BLOWPIPE    PRACTICE. 

over  the  opening  of  the  tube.  Most  ammonium  compounds  impart 
a  feeble  blueish-green  or  brownish-green  colour  to  the  flame,  but 
none  give  a  distinctive  spectrum. 


§6. 
PLAN  OF  ANALYSIS. 

In  the  examination  of  a  mineral  substance  with  a  view  to  determine 
its  general  nature  by  the  blowpipe — aided  by  such  liquid  reagents 
and  processes  as  are  available  in  blowpipe  practice — it  is  advisable,  in 
the  first  place,  to  determine  the  electro-negative  element  or  compound 
in  the  substance  (or,  in  other  words,  to  ascertain  the  chemical  group 
to  which  the  substance  belongs),  and  afterwards  to  determine  the 
base  or  bases  that  may  be  present  in  it. 

The  methods  of  Blowpipe  Analysis  usually  followed,  although  well 
adapted  to  convey  a  knowledge  of  the  special  reactions  of  bodies, 
have  two  essential  defects  :  they  draw  no  line  of  separation  between 
electro-negative  substances  and  bases,  but  mix  up  the  two  together 
in  a  loose  and  confusing  manner ;  and  they  exact  the  performance 
of  a  great  number  of  experiments,  by  which  many  substances  are 
detected  over  and  over  again,  whilst  others  may  easily  escape  detec- 
tion altogether. 

In  the  plan  now  proposed,  these  defects  are  in  a  great  measure 
remedied,  and  a  knowledge  of  the  chemical  nature  of  an  unknown 
mineral — so  far  as  this  epi  be  obtained  by  the  Blowpipe— is  arrived 
at  without  unnecessary  trouble  or  delay.  If  the  electro-negative 
principle  in  the  substance  be  not  detected  by  one  or  the  other  of  the 
eight  easily  and  rapidly  performed  experiments  given  under  the  first 
section  of  the  scheme,  the  substance— unless  it  be  a  telluride,  tanta- 
late  or  other  rare  compound,  properly  omitted  from  consideration  in 
an  outline  of  the  present  character — will  be  either  a  simple  basic- 
oxide  or  metal,  and  its  true  nature  will  be  revealed  in  the  examina- 
tion for  bases,  as  given  under  TABLE  B.  It  will,  of  course,  be 
understood,  that,  as  a  rule,  the  entire  series  of  experiments  for  the 
detection  of  electro-negative  bodies  need  not  be  carried  out.  Sulphates, 
for  example,  will  be  recognized  by  the  first  experiment,  carbonates 
and  silicates  bv  the  second,  and  so  on  as  regards  representatives  of 
other  groups.  Except,  therefore,  in  certain  rare  cases  indicated  in 
the  text  (as  in  the  combination  of  a  phosphate  and  fluoride,  &c.),  it 


PLAN    OF    ANALYSIS. 


61 


will  only  be  necessary  to  continue  the  experiments  until  the  chemical 
group  to  which  the  substance  essentially  belongs  has  been  ascertained. 
The  base  or  bases,  present  in  the  substance,  may  then  at  once  be 
sought  for. 

A.— DETECTION  OF  ELECTRO-NEGATIVE  BODIES. 


EXPERIMENTS. 

RESULTS  MORE  ESPECIALLY 

SUBSTANCES  INDICATED. 

TO  BE  LOOKED  FOR. 

1.  Fuse    the  test-sub- 

(1) Emission  of  arseni- 

(1) As.,  Arsenides,  Ar- 

stance,  in  powder,  with 

cal  odour. 

seniates. 

carb.  soda  (and  a  small 
addition  of  borax)  in  R. 

(2)  Emission  of  copious 
fumes,  and  deposition  of 

(1  and  3)  AaS.,    As2S3, 
Stilpharsenites. 

F.  on  charcoal. 

dense  white  coating  on 

(2  and   3)    Sb2S3;   Sul- 

Moisten  fused   mass, 

the  charcoal. 

phantimonites. 

and  place  on   lead  test- 

(3)  Formation  of  "he- 

(3)  8.    Sulphides,    Sul- 

paper or  silver-foil. 

par,"  or  alkaline  sulph- 

phates,    also    the     rare 

ide. 

Selenides. 

N.  B.-If  the  fa  sion  be  effected 

by  a  gas  flame,  the  gas  should 

Other  results  (if  any)  such 

See  special  reactions  §  5,  for 

be  tested  previously  for  pres- 
ence of  sulphur.     'See  under 

as  reduction  to  metal,  yellow 
coating  on  charcoal,  &c.  ,  may 

distinctive    and    confirmatory 
characters. 

"Sulphur  "ing  5. 

be  noted  down  for  after  refer- 

ence. 

2.  Fuse   solid  particle 
of    test-substance    with 

(1)  Very  slow  solution, 
with  formation  of  silica- 

(1)  Silica,     Silicates 
generally. 

(previously  fused)  bead  of 
phosphor-salt    on    plati- 
num wire. 

skeleton    or    opalescent 
bead. 
(2)  Rapid  solution,  ac- 
companied    throughout 
by  effervescence. 

(2)  Carbonates    (also 
bodies   which   evolve 
oxygen,  as  MnO2,  Bichro- 
mates, Chlorates,  &c.  ). 

Other  results  (as  rapid  solu- 

Confirmatory tests.—  For  SiO2, 

tion     without    effervescence, 

fuse  with  carb.  soda.     Heat,  in 

&e.),  may  be  noted  down,  but 

test-tube,  with   HC   acid   (for 

are  not  to  be  taken  into  ac- 

gelatinization, &c.).     For  Car- 

count here. 

bonates,  warm,  in    test-tube, 

with  dilute  HC  acid  (for  effer- 

vesence). 

3.  Fuse  test-substance 

Rich  azure  blue  flame. 

Chlorides. 

in  powder  with  phosphor- 
salt  and  copper  oxide  on 
plat,  wire,  or  with  phos- 
phor-salt alone  on  copper 

NOTE.  —  If  a  blue  and  green, 
or  an   intensely  vivid    green 
flame  be  produced,  Br.  and  I 
may  be  suspected,  but  natural 

Also,    chloro-phosphates    (a» 
pyromorphite,   many  apatites, 
&c.)  Confirm  by  Experiment  4. 

wire. 

Bromides  and  Iodides  are  of 

very  rare   occurrence.      Test 

with  (dry)  bisulphate  of  pot- 

ash in  closed  tube  over  Bun- 

sen  flame  (for  yellow  or  violet 

fumes). 

62  BLOWPIPE    PRACTICE. 

DETECTION  OF  ELECTRO-NEGATIVE  BODIES-(CWtm<e<?). 


EXPERIMENTS. 

RESULTS  MORE  ESPECIALLY 
TO  BE  LOOKED  FOR.    • 

SUBSTANCES  INDICATED 

4.  Boil  the  substance, 
in   fine   powder,    with   a 
few  drops  of  nitric  acid 
in  a  test,tube.     Half  -till 
the  tube  with  water,  drop 
into  the  solution  a  frag 
ment  of  amm.  molybdate, 
and  warm  gently. 

A    canary-yellow    pre- 
cipitate. 

Phosphates. 

NOTE.  —  Most  phosphates, 
especially  if   moistened    with 
sulphuric  acid,  impart  a  green 
Inge  to  the  flame. 
Many  natural  phosphates  are 
combined    with    chlorides    or 
iuorldes,  or  with  both.     01.,  if 
^resent,  will  have  been  detected 
>y  Expt.  3  ;  Fl.  must  besought 
for  by  Expt.  6. 

5.  Warm  the  test-sub- 
stance, in  powder,  with  a 
few   drops    of    sulphuric 
acid,  add  a  little  alcohol, 
stir  and  inflame  the  mix- 
ture. 

(1)  A  deep-green  solu- 
tion. 
(2)  A  rich  blue   solu- 
tion. 
(3)  A  green  coloration 
of  the  flame. 

NOTE.—  A  green  flame  is  pro- 
duced by  tnost  borates  per  se, 
in  all,  by  moistening  the  test- 
substance  with  sulphuric  aoid, 
or  with  glycerine.  Phosphates, 
however,  produce  the  same  re- 
action when  thus  treated,  but' 
do  not  give  a  green  flame  with 
alcohol. 

(1)  Chromates. 
(2)  Molybdates, 

(3)  Borates,  also  '  '  Boro- 
Silicates.''  , 

NOTE.  —  Small    portions     of 
B2O3    in    silicates,    &c.,    m»y 
escape  detection  by  this  Expt. 
but  the  object  of  the  present 
scheme  is  not  to  detect  minute 
or  inessential  components,  but 
to     determine     the    chemical 
group  to  which  the  test-sub- 
stance may  belong.    See  under 
Reactions,  §  5. 

6.  Heat  the  substance, 
in  powder,  with   a  few 
drops  of  strong  sulphuric 
acid  in  a  narrow  test-tube. 

(1)  Corrosion  of  inside 
of    tube.       (Wash    out 
thoroughly,  and  dry  be- 
fore coming  to   conclu- 
sion. ) 
(2)  Evolution  of  ruddy 
(nitrous)  fumes. 

(1)  Fluorides,  also  com- 
binations    of     Fluorides 
and  Phosphates  (see  under 
Expt.  4  above). 

(2)  Nitrates. 
Confirmatory  test  for  nitrates. 
—  Ignite  on  charcoal  (for  defla- 
grescence), 

7.  Fuse  teat-substance, 
in  fine  powder,  with  about 
3  parts  of  oarb.  soda  and 
2  nitre  inaplatinum  spoon 
or  loop  of  platinum  wire. 
Dissolve  resulting  soluble 
matters    in    hot    water; 
decant  clear  solutipn  into 
a  small  porcelain  capsule, 
add  a  few  drops  of  hydro- 
chloric acid,  and  place  in 
the   solution    a   piece  of 
zinc. 

A  dark-blue  coloration. 

NOTE.  -  -  Molybdenum    com- 
pounds when  thus  treated  maj 
also  produce  a  blue  coloration 
at  first,  but  this,  on  standing, 
becomes  rapidly  dark  brown. 

(1)  Tungstates. 

If  much  MnO  be  present  (as 
in  Wolfram),  the  solution  will 
at  first  be  green,  but  this  dis- 
appears   rapidly    on    heating, 
and     the     solution     beoom<  s 
nearly  colorless  and  then  deen 
indigo-blue. 

PLAN    OP    ANALYSIS. 
DETECTION  OF  ELECTRO-NEGATIVE  BODIES— (Continued). 


63 


EXPERIMENTS. 

RESULTS  MOKE  ESPECIALLY 
TO  BE  LOOKED  FOR; 

SUBSTANCES  INDICATED. 

8.  Fuse  test-substance, 
in  fine  powder,  with  5  or 
6  parts  of  bisulphate  pot- 
ash (added  successively^ 
in  platinum  spoon  or  wire 
loop.  Dissolve  out  in 
slightly  warm  water, 
decant  and  boil. 

A  white   or    pale-yel- 
lowish precipitate',  chang- 
ing to  a  violet  or  amethy- 
stine colour  if  Warmed 
with   hydrochloric   acid 
and  a  piece  of  2inc  or 
tin-foil.     (See  page  51.) 

Titanic  Acid. 
Titaniates. 

Confirmatory   test.  —  Fuse   a 
portion    of    the     principitate 
with    phosphor-salt    on    plat, 
wire.     See  Reactions,  §  6. 

B.—  DETECTION  OF  BASES. 

In  many  minerals,  the  so-called  base — -lead,  for  example,  in  sul- 
phide of  lead,  copper  in  red  or  black  oxide  of  copper,  baryta  in  car- 
bonate of  baryta,  and  so  forth — may  be  easily  recognized  by  the  use 
of  the  blowpipe.  This  is  especially  the  case,  when  the  base  consists 
of  a  single  and  easily  reducible  metal  or  metallic  oxide,  such  as  silver, 
lead,  copper,  tin,  &c. ;  or  where  it  imparts  a  colour  to  borax  or  other 
reagent,  as  in  the  case  of  copper,  iron,  cobalt,  nickel,  manganese,  &c. ; 
or  where  it  forms  a  deposit  on  charcoal,  communicates  a  colour  to 
the  flame,  or  exhibits  other  characteristic  reactions.  Even  when 
several  bodies  of  this  kind  are  present,  their  recognition,  as  a  general 
rule,  is  easily  effected.  Earthy  and  alkaline  bases,  when  in  the  form 
of  carbonates,  sulphates,  phosphates,  fluorides,  &c.,  can  also  be  made 
out,  in  general,  without  difficulty,  unless  several  happen  to  be  present 
together,  in  which  case  it  is  not  always  possible,  by  the  simple  aid  of 
the  blowpipe,  to  distinguish  them  individually.  When  these  bases 
are  combined  with  silica,  on  the  other  hand,  the  blowpipe  alone  is 
rarely  sufficient  for  their  detection.  This,  however,  so  far  as  practical 
purposes  are  concerned,  is  of  little  consequence,  as  no  economic  valuer 
in  silicates  of  this  character,  is  dependent  on  the  base.  In  general 
cases,  four  experiments  only  will  be  required.  These  comprise  : 
Testing  for  water  by  ignition  in  the  bulb-tube ;  fusion  or  ignition  of 
the  substance  per  se ;  fusion  with  carb.  soda  ;  and  fusion  with  borax. 
It  will  thus  be  seen  that,  in  many  oases,  the  nature  of  the  base  will 
be  sufficiently  revealed  by  the  reactions  which  ensue  during  the 
determination  of  the  electro-negative  character  of  the  substance. 


BLOWPIPE    PRACTICE. 


EXPERIMENTS. 


RESULTS  MORE  ESPFCIALLY  TO 
BE  LOOKED  FOR. 


SUBSTANCES  INDICATED. 


1.  Ignite  in  bulb-tube. 


( 1 )  Presence  of  moisture 

(2)  Assumption  of  dark 


NoTE.-This  experiment  may  !  co]our  and  magnetism. 


be  omitted  as  a  rule  in  the  case 
of  minerals  of  metallic  aspect. 


Other  results  (if  any)  may  be 
|  disregarded. 


1.  Water. 

Test  with  blue  and  red  litmus 
papers. 

2.  Iron,  probably  as  FeO. 


2.  Ignite  or  fuse  per  se 
in  platinum  forceps,  or,  if 
metallic,  on  charcoal. 


3.  Fuse  (after  thorough 
roasting,  if  necessary) 
with  carb,  soda  and  a  little 
borax  on  charcoal ;  or,  if 
the  substance  present  a 
non  -metallic  aspect,  on 
platinum  wire. 


( 1 )  Coloration  of  flame : 
«  Red  flame;  1*  Yellowflame; 
lc  Green  flame  ;  1<*  Blue  flame  ; 
Violet  flame. 


(2)  Ring-deposit  on  char- 
coal : 

2«  White  dep.  ;  2&  Red-brown 
dep. ;  2c  Yellow  dep. 


(3)  Assumption  of  mag- 
netism. 

(4)  Assumption  of  caus- 
ticity.    (Page  9.) 

Other  results  (if  any)  may  be 
disregarded. 


(1)  White   or   yellow 
ring-deposit  on  charcoal. 

(2)  Reduced  metal : 

2*  Fusible,  non-oxidizable 
globule;  26Infus.,  non-ox,  par- 
ticles ;  i;c  Infusible,  oxidizable, 
magnetic  particles;  2d  Fusible, 
oxid.,  mm-volatile globules  ;  2« 
Fusible,  volatilizable  globules. 

(3)  A    green-blue  tur- 
quoise enamel. 

(4)  Complete    solution 
(with   absorption,  if  on 
charcoal). 


(l)a  Lithia,  strontia, 
lime. 

(I)6  Soda 

(l)c  Copper,  antimony, 
zinc,  molybdenum,  baryta, 
ammonia. 

ld  Lead.  (Also  CuCl, 
&c.) 

1«  Potash. 

See  Reactions,  §  5,  and  Ad- 
dendum to  Table  B,  below  The 
student  must  remember  that 
certain  electro-negative  bodies, 
S,  P2O&.  B2()8,  &e.,  also  give  col- 
oured flames. 

2a  Antimony  (yellowish, 
hot);  arsenic ;  zinc  (yellow 
and  phosphorescent,  hot); 
molybdenum  (yellowish, 
hot) ;  tin  (very  slight). 

26  Cadmium. 

2C  Bismuth  ;  lead  ;  zinc 
(whilst  hot). 

See  Addendum,  below. 

*3.   Iron. 

4.  Alkaline  earths 
(CaO.  &c.)  in  carbonates, 
sulphates,  fluorides,  &c. 


(1)  See  under  Expt.  2; 
also  the  Addendum  below. 

(2)«  Gold ;  Silver. 

(2)5  Platinum. 

(2)c  Iron,  Nickel,  Cobalt 

2d  Copper  ;  Tin  (practi- 
cally). 

2e  Bismuth  ;  Lead ;  An- 
timony. 

(3)  Manganese. 

(4)  Baryta  ;     Strontia  ; 
Alkalies. 

See  Addendum,  below. 


PLAN    OF   ANALYSIS. 


65 


DETECTION  OF  BASKS -(Confined). 


EXPERIMENTS. 


4.  Fuse  with  borax  on 
platinum  wire  (after 
thorough  roasting,  if  ne- 
cessary). 


5.  Additional  experi- 
ments— (as  ignition  with 
cobalt  solution  ;  testing 
for  Hg.  with  reducing 
agents  in  closed  tube ;  cu- 
pellation,  &c. , )  if  thought 
necessary  by  physical 
characters  of  the  test- 
substance,  or  by  indica- 
tions resulting  from  the 
above  blowpipe  trials. 


RESULTS  MORE  ESPECIALLY  to 
BE  LOOKED  FOR. 


(1)  A  coloured  bead 
which  becomes  turbid  or 
opaque  (from  reduction  or 
partial  reduction)  in  the 
RF. 


(2)  A  coloured  bead,  not 
becoming  opaque  in  RF. 

(3)  A  colourless  bead, 
not  affected  by  flaming. 

(4)  A    colourless  bead 
which  becomes  opaque  on 
saturation  or  by  naming. 


SUBSTANCES  INDICATED. 


(1)  Copper  ;  Nickel  ; 
Cerium  ;  Uranium  (the 
glass  becomesblackinRF). 

Also  Molydenum  (to 
some  e  x  tent )  ,Tungstenum 
and  Titanium  ;  but  these 
metals  occur  mostly  in 
minerals  as  oxidized  elec- 
tro-negatives, and  thua 
come  under  detection  in 
TABLE  A. 

(2>  Manganese  ;  Chro- 
mium (see  Table  A) ;  Iron ; 
Cobalt. 

(3)  Alumina  ;  Tin  oxide 
(to  some  extent).     Both 
very  slowly  attacked. 

(4)  Zirconia  ;    Glucina  ; 
Yttria ;  Zinc  oxide ;  Alka- 
line earths   (MgO,    CaO, 
etc.);  Alkalies. 


ADDENDUM  TO  TABLE  B. 

A  Classification,  according  to  their  Blowpipe  Characters,  of  the  more  commonly 
occurring  Mineral  Bases, 

SECTION  1. — GIVING  per  se,  OR  WITH  CARD.  SODA,  ON  CHARCOAL, 

METALLIC   GLOBULES    OR    METALLIC    GRAINS. 


Group  1. — Yielding  malleable  metallic  globules,  without  deposit  on 
the  charcoal. 
6 


66  BLOWPIPE    PRACTICE. 

Gold.     Silver.     Copper. 

Gold  is  insoluble  in  the  fluxes.  Silver  is  not  oxidized  per  se,  but 
retains  a  bright  surface  after  exposure  to  an  oxidating  flame.  Copper 
becomes  encrusted  on  cooling  with  a  black  coating.  It  imparts  a 
green  colour  to  the  flame-border ;  and  forms  strongly  coloured  glasses 
with  borax  and  phosphor-salt :  (green  (hot),  blue  (cold),  in  O  F  : 
red-brown,  opaque,  in  R  F  :  see  above).  Gold  and  silver  may  be 
separated  from  copper,  &c.,  by  fusion  with  lead,  and  subsequent 
cupellation.  If  gold  and  silver  be  present  together,  the  bead  is 
generally  more  or  less  white.  By  fusing  it  in  a  small  platinum- 
spoon  with  bisulphate  of  potash,  the  silver  dissolves,  and  the  surface 
of  the  globule  becomes  yellow.  If  the  globule  be  flattened  out  into 
a  disc  on  the  anvil,  before  treatment  with  bisulphate  of  potash,  tha 
silver  is  more  rapidly  extracted.  The  sulphate  of  silver  must  be 
removed  by  treating  the  spoon,  in  a  porcelain  or  platinum  capsule, 
with  a  small  quantity  of  water,  over  the  spirit-lamp.  By  evaporation, 
and  fusion  of  the  residuum  with  carb.  soda  on  charcoal,  metallic  silver 
can  be  again  obtained. 

Group  2. — Yielding  infusible  metallic  grains,  without  deposit  on  the 
charcoal. 

Platinum.     Iron.     Nickel.     Cobalt.     Molybdenum.     Tungstenum. 

Platinum  is  not  attacked  by  the  blowpipe  fluxes.  Iron,  Nickel,  and 
Cobalt,  or  their  oxides,  are  readily  dissolved  by  fusion  with  borax  or 
phosphor-salt,  producing  a  coloured  glass.  (See  under  "  Borax,"  pages 
13,  14,  above.)  These  metals  are  also  magnetic.  As  a  general  rale 
if  a  substance  become  attractable  by  the  magnet  after  exposure  to  the 
blowpipe,  the  presence  of  iron  may  be  inferred,  cobalt  and  nickel  com- 
pounds being  comparatively  rare.  The  presence  of  cobalt  is  readily 
detected  by  the  rich  blue  colour  of  the  borax  and  phosphor-salt  glasses, 
in  both  an  oxidating  and  reducing  flame ;  but  if  much  iron  be  present 
also,  the  glass  is  bluish-green.  With  borax  in  the  R  F,  nickel  com- 
pounds give  reduced  metal,  and  the  glass  becomes  gray  and  troubled. 
Molybdenum  and  Tungstenum  give  non-magnetic  grains  of  reduced 
metal.  They  are  commonly  present  in  minerals  as  the  electro-nega- 
tive principle,  and  their  presence  is  best  detected  by  the  method  given 
under  Experiment  7,  Table  A,  above. 


PLAN   OF   ANALYSIS*  67 

Group  3. — -Yielding  metallic  globules,  with  white  or  yellow  deposit 
on  the  charcoal. 

Tin.     Lead.     Bismuth.     Antimony. 

Tin  and  Lead  give  malleable  globules.*  The  sublimate  formed  by 
tin  is  white,  small  in  quantity,  and  deposited  on,  and  immediately 
around,  the  globuler  The  lead  sublimate  is  yellow,  and  more  or  less 
copious.  Bismuth  and  Antimony  give  brittle  globules.  The  bismuth 
sublimate  is  dark  yellow ;  the  antimony  sublimate,  white,  and  very 
abundant.  Lead  imparts  a  clear  blue  colour  to  the  flame-border ; 
antimony,  a  greenish  tint.  As  a  general  rule,  a  yellow  deposit  on  the 
charcoal  may  be  regarded  as  indicative  of  the  presence  of  lead;  whilst, 
the  emission  of  copious  fumes,  and  deposition  of  a  white  coating  on  the 
charcoal,  may  be  safely  considered  to  indicate  antimony.  The  coating 
or  sublimate  formed  by  zinc  (see  below),  although  white  when  cold, 
is  lemon-yellow  whilst  hot.  The  rare  metal,  tellurium,  closely  resem- 
bles antimony  in  its  reactions,  but  if  warmed  with  concentrated  sul- 
phuric acid,  it  forms  a  reddish-purple  solution. 

NOTE. — An  excellent  method  of  distinguishing  the  blowpipe-subli- 
mates of  lead,  bismuth,  antimony,  and  also  cadmium,  has  been 
recently  discovered  by  Dr.  Eugene  Haanel,  of  Victoria  College, 
Cobourg  (Ontario).  Moistened  with  a  drop  of  hydriodic  acid,  and 
ignited,  the  lead  sublimate  becomes  bright  canary-yellow;  the  bismuth 
sublimate,  chocolate-brown  ;  the  antimony  sublimate,  bright  red ;  and 
the  cadmium  sublimate,  white.  The  hydriodic  acid  is  obtained  by 
steeping  iodine  in  water,  and  passing  through  the  liquid  a  current  of 
sulphuretted  hydrogen  until  it  becomes  clear.  The  reactions  pro- 
duced by  this  method  are  remarkably  distinct. 

SECTION  2. — REDUCIBLE,  BUT  YIELDING  NO  METAL  ON  CHARCOAL. 
(This  arises  from  the  rapid  volatilization  of  the  reduced  metal.) 

Group  1. —  Volatilizing  without  odour,  and  without  formation  of  a 
deposit  on  the  charcoal. 

Mercury. 

For  the  proper  detection  of  this  metal,  a  small  portion  of  the  test- 
substance  in  powder  must  be  mixed  with  some  previously  dried  carb. 

*  See  in  the  Appendix,  No.  21,  the  striking  reaction  manifested  by  alloys  of  these  metals. 


68  BLOWPIPE   PRACTICE. 

soda,  and  the  mixture  strongly  ignited  at  the  bottom  of  a  small  tube 
or  narrow  flask.  If  mercury  be  present,  a  gray  sublimate  will  be 
formed.  This  may  be  collected  by  friction  with  a  wire,  &c.,  into 
small  metallic  globules,  and  poured  out  of  the  tube.  If  some  iron 
filings  be  mixed  with  the  carb.  soda,  the  mercurial  sublimate  is  more 
readily  obtained. 

Group  2. —  Volatilizing  without  odour,  but  forming  a  deposit  on  the 
charcoal. 

Cadmium.     Zinc. 

The  deposit  produced  by  cadmium  is  dark  yellowish-brown  or  red- 
dish-brown. That  produced  by  zinc  is  lemon-yellow  and  phosphor- 
escent whilst  hot,  and  white  when  cold.  If  moistened  with  a  drop 
of  nitrate  of  cobalt  and  ignited,  it  becomes  bright  green.* 

Group  3. — Volatilizing  with  strong  odour  of  garlic. 

Arsenic  (more  commonly  present  in  minerals  as  an  electro-negative 
body.  See  Table  A,  above). 

The  alliaceous  or  garlic  like  odour  is  most  readily  developed  when 
the  test-matter  is  mixed  with  some  carb.  soda,  or  other  reducing  flux, 
and  exposed  on  charcoal  to  the  action  of  a  reducing  flame. 

The  presence  of  arsenic  may  also  be  proved  as  follows :  (1) 
By  roasting  a.  fragment  of  the  substance  in  an  open  glass  tube, 
when  minute  octahedrons  of  arsenious  acid  (easily  recognized  by  their 
triangular  faces  if  examined  by  a  common  lens)  will  be  deposited  at 
the  upper  end  of  the  tube ;  and  (2),  by  igniting  the  test-substance, 
mixed  with  some  dry  oxalate  of  potash  or  cyanide  of  potassium,  at 
the  bottom  of  a  small  flask  or  closed  tube,  when  a  dark,  shining  subli- 
mate of  metallic  arsenic  will  be  produced.  Without  the  reducing 
flux,  a  yellow  or  yellowish-red  sublimate  of  arsenical  sulphide  might 
be  formed  in  certain  cases. 

SECTION  3. — NOT  REDUCIBLE  BEFORE  THE  BLOWPIPE. 

Group  1. — Imparting  a  colour  to  borax. 

Manganese.  Chromium.  Titanium.  (The  two  latter  are  com- 
tnonly  present  in  minerals  as  electro-negative  bodies.) 

*  In  testing  a  substance  supposed  to  contain  cadmium,  a  little  chalk-powder  or  bone  ash  may 
lie  rubbed  over  the  surface  of  the  charcoal.  If  cadmium  be  present,  its  reddish-brown  subli- 
mate (CdO)  is  then  more  readily  seen. 


PLAN    OF   ANALYSIS.  69 

Manganese  compounds  impart,  before  an  oxidating  flame,  a  violet 
colour  to  borax ;  Chromium  compounds,  a  clear  green  colour.  (See 
also  under  "  Carbonate  of  Soda,"  page  15,  above.)  Titanium  com- 
pounds form,  with  borax  in  the  E-  F,  a  brownish-amethystine  glass, 
which  becomes  light  blue  and  opaque  by  naming.  The  presence  of 
titanium  in  minerals  is  most  readily  detected  by  fusing  the  substance 
in  very  fine  powder  with  3  or  4  parts  of  carb.  soda  in  a  platinum  spoon, 
dissolving  the  fused  mass  in  hydrochloric  acid,  diluting  slightly,  and 
then  boiling  with  a  slip  of  tin  or  zinc.  The  solution,  if  titanium  be 
present,  will  gradually  assume  an  amethystine  tint.  Or,  the  sub- 
stance, in  fine  powder,  may  be  fused  with  bisulphate  of  potash  in  suc- 
cessive portions.  The  titanic  acid  by  this  treatment  becomes  soluble 
in  water,  from  which  it  may  be  precipitated  as  a  white  or  slightly 
yellowish  powder  by  boiling.  The  precipitate  can  then  be  fused 
before  the  blowpipe  in  a  reducing  flame  with  some  phosphor-salt,  when 
a  violet-coloured  or  amethystine  bead  will  result.  If  iron  be  present 
in  the  substance,  a  drop  or  two  of  hydrochloric  acid  should  be  added 
to  the  solution  before  the  precipitation  of  the  titanic  acid. 

The  rare  metals,  cerium,  uranium,  &c.,  belong  also  to  this  group. 
Reference  should  also  be  made  to  iron,  nickel,  cobalt  and  copper,  as 
the  oxides  of  these  latter  metals,  if  in  small  quantity,  might  escape 
detection  by  the  reducing  process.  (See  under  Operation  5,  pp.  13, 
14,  the  colours  imparted  by  these  oxides  to  borax.) 

Group  2. — Imparting  no  colour  to  the  fluxes.  Slowly  dissolved  by 
borax,  the  glass  remaining  permanently  clear. 

Alumina. 

Moistened  with  nitrate  of  cobalt  and  then  ignited,  this  base  assumes 
on  cooling  a  fine  blue  colour. 

Group  3. — Imparting  no  colour  to  the  fluxes.  Rapidly  dissolved 
by  borax,  the  glass  becoming  opaque  on  cooling  or  when  flamed.  In- 
soluble in  carb.  soda. 

Magnesia.     Lime. 

Moistened  with  nitrate  of  cobalt,  and  ignited,  Magnesia  becomes 
pale-red  in  colour ;  Lime,  dark  gray. 


70  BLOWPIPE   PRACTICE. 

Group  4. — Entirely  dissolved  by  fusion  with  carl),  soda. 

Baryta.     Strontia.     Lithia.     Soda.     Potash. 

Baryta  compounds  impart  a  distinct  green  colour  to  the  point  and 
border  of  the  flame.  Strontia  and  Lithia  colour  the  flame  deep  car- 
mine-red. The  crimson  coloration  is  destroyed  in  the  case  of  strontia 
if  the  substance  be  fused  with  chloride  of  barium.  Soda  colours  the 
flame  strongly  yellow.  Potash  communicates  to  it  a  violet  tint ;  but 
this  colour  is  completely  masked  by  the  presence  of  soda,  unless  the 
flame  be  examined  through  a  deep  blue  glass.  See  also  the  spectro- 
scope reactions  of  these  bodies  given  under  their  respective  heads  in 
§5. 


APPENDIX. 


ORIGINAL  CONTRIBUTIONS  TO  BLOWPIPE  ANALYSIS. 


BY  E.  J.  CHAPMAN. 


1.— EEACTION  OF  MANGANESE  SALTS  ON  BARYTA. 
When  moistened  with  a  solution  of  any  manganese  salt,  and  ignited 
in  an  oxidating  flame,  baryta  and  baiyta  compounds,  generally, 
assume  on  cooling  a  blue  or  greenish-blue  colour.  This  arises  from 
the  formation  of  a  manganate  of  baryta.  Strontia  and  other  bodies 
(apart  from  the  alkalies)  when  treated  in  this  manner,  become  brown 
or  dark-gray.  A  mixture  of  baryta  and  strontia  also  assumes  an 
indefinite  grayish-brown  colour.  If  some  oxide  of  manganese  be 
fused  with  carbonate  of  soda  so  as  to  produce  a  greenish-blue  bead  or 
"  turquoise  enamel,"  and  some  baryta  or  a  baryta  salt  be  melted  into 
this,  the  colour  of  the  bead  will  remain  unchanged  ;  but  if  strontia  be 
used  in  place  of  baryta,  a  brown  or  grayish-brown  enamel  is  produced. 
NOTE. — Some  examples  of  witherite,  barytine,  and  baryto-calcite,  contain 
traces  of  oxide  of  manganese.  These,  after  strong  ignition,  often  assume  per  se 
a  pale  greenish-blue  colour.  1846. 

2.— DETECTION  OF  BARYTA  IN  THE  PRESENCE  OF  STRONTIA, 
This  test  is  chiefly  applicable  to  the  detection  of  baryta  in  the 
natural  sulphate  of  strontia ;  but  it  answers  equally  for  the  examina- 
tion of  chemical  precipitates,  &c.,  in  which  baryta  and  strontia  may 
be  present  together.  The  test-matter,  in  fine  powder,  is  to  be  melted 
in  a  platinum  spoon  with  3  or  4  volumes  of  chloride  of  calcium,  and 
the  fused  mass  treated  with  boiling  water.  For  this  purpose,  the 
spoon  may  be  dropped  into  a  teat-tube,  or  placed  (bottom  upwards) 
in  a  small  porcelain  capsule.  The  clear  solution,  decanted  from  any 
residue  that  may  remain,  is  then  to  be-  diluted  with  8  or  10  times 
its  volume  of  water,  and  tested  with  a  few  drops  of  chromate  (or 
bichromate)  of  potash.  A  precipitate,  or  turbidity,  indicates  the 
presence  of  baryta.  1846. 


72  BLOWPIPE    PRACTICE. 

3.— DETECTION  OF  ALKALIES  IN  THE  PRESENCE  OF  MAGNESIA. 
In  the  analysis  of  inorganic  bodies,  magnesia  and  the  alkalies  (if 
present)  become  separated  from  other  constituents  towards  the  close 
of  the  operation.  In  continuation  of  the  analysis,  it  then  becomes 
desirable  to  ascertain,  at  once,  whether  magnesia  be  alone  present,  or 
whether  the  saline  mass,  produced  by  the  evaporation  of  a  portion  of 
the  solution,  consist  of  magnesia  and  one  or  more  of  the  alkalies,  or 
of  the  latter  only.  By  fusing  a  small  quantity  of  the  test-matter  with 
carbonate  of  soda,  the  presence  of  magnesia  is  readily  detected,  as  this 
substance  remains  undissolved ;  but  the  presence  or  absence  of  alka- 
lies is  not  so  easily  determined,  the  coloration  of  the  flame  being 
frequently  of  too  indefinite  a  character  to  afford  any  certain  evidence 
on  this  point.  The  question  may  be  solved,  however,  by  the  following 
simple  process.  Some  boracic  acid  is  to  be  mixed  with  the  test-matter 
and  with  a  few  particles  of  oxide  of  copper,  and  the  mixture  is  to  be 
exposed  for  a  few  seconds,  on  a  loop  of  platinum  wire,  to  the  action  of 
an  oxidating  flame.  In  the  absence  of  alkalies,  the  oxide  of  copper 
will  remain  undissolved  ;  but  if  alkalies  be  present,  an  alkaline  borate 
is  produced,  forming  a  readily  fusible  glass,  in  \vhich  the  copper  oxide 
is  at  once  dissolved,  the  glass  becoming  green  whilst  hot,  and  blue 
when  cold.  If  magnesia  also  be  present,  white  specks  remain  for  a 
time  undissolved  in  the  centre  or  on  the  surface  of  the  bead.  Any 
metallic  oxide  which  imparts  by  fusion  a  colour  to  alkaline  borates, 
may,  of  course,  be  employed  in  place  of  oxide  of  copper;  but  the 
latter  has  long  been  used  in  other  operations,  and  is  therefore  always 
carried  amongst  the  reagents  of  the  blowpipe-case.  1847. 

4.— METHOD  OF  DISTINGUISHING  THE  RED  FLAME  OF  LITHIUM 
FROM  THAT  OF  STRONTIUM. 

It  has  been  long  known  that  the  crimson  coloration  imparted  to  the 
blowpipe-flame  by  strontia,  is  destroyed  by  the  presence  of  baryta. 
This  reaction,  confirmed  by  Plattner  (see,  more  especially,  the  third 
edition  of  his  "  Probirkunst,"  page  107),  was  observed  as  early  as 
1829  by  Butsengeiger  ("Annales  des  Mines,"  t  v.,  p.  36).  The 
latter  substance,  however,  as  first  indicated  by  the  writer,  does  not 
affect  the  crimson  flame-coloration  produced  by  lithia.  Hence,  to  dis- 
tinguish the  two  flames,  the  test-substance  may  be  fused  with  2  or  3 
volumes  of  chloride  of  barium  on  a  loop  of  platinum  wire,  the  fused 


APPENDIX.  73 

mass  being  kept  just  within  the  point  or  edge  of  the  blue  cone.  If 
the  original  flame-coloration  proceeded  from  strontia  (or  lime),  an 
impure  brownish-yellow  tinge  will  be  imparted  to  the  flame-border ; 
but  if  the  original  red  colour  were  caused  by  lithia,  it  will  not  only 
remain  undestroyed,  but  its  intensity  will  be  much  increased. 

This  test  may  be  applied,  amongst  other  bodies,  to  the  natural 
silicates,  lepidolite,  spodumene,  <fcc.  It  is  equally  available,  also,  in 
the  examination  of  phosphates.  The  mineral  triphylline,  for  example, 
when  treated  per  se,  imparts  a  green  tint  to  the  point  of  the  flame, 
owing  to  the  presence  of  phosphoric  acid  ;  but  if  this  mineral  be  fused 
(in  powder)  with  chloride  of  barium,  a  beautiful  crimson  coloration  in 
the  surrounding  flame-border  is  at  once  produced.  1848. 

5. -METHOD  OF  DISTINGUISHING  THE  MONOXIDE  OF  IKON 
(FeO)  FROM  THE  SESQUIOXIDE  (Fe2O3)  IN  SILICATES  AND 
OTHER  COMPOUNDS. 

If  iron  be  recognized  in  an  oxidized  body,  its  presence  or  absence 
as  ferrous  oxide  (FeO)  is  readily  indicated  by  this  test :  assuming, 
of  course,  that  no  other  reducing  body  be  present,  a  point  easily 
ascertained  by  the  blowpipe.  The  test  is  performed  as  follows  :  A 
small  quantity  of  black  oxide  of  copper  (CuO)  is  dissolved  in  a  bead 
of  borax  on  platinum  wire,  so  as  to  form  a  glass  which  exhibits,  011 
cooling,  a  decided  blue  colour,  but  which  remains  transparent.  To 
this,  the  test-substance  in  the  form  of  powder  is  added,  and  the  whole 
is  exposed  for  a  few  seconds,  or  until  the  test-matter  begin  to  dissolve, 
co  the  point  of  the  blue  flame.  If  the  substance  contain  Fe2O3  only, 
the  glass  on  cooling  will  remain  transparent,  and  will  exhibit  a  bluish- 
green  colour.  On  the  other  hand,  if  the  test-substance  contain  FeO, 
this  will  become  at  once  converted  into  Fe2O3  at. the  expense  of  some 
of  the  oxygen  of  the  copper  compound ;  and  opaque  red  streaks  and 
spots  of  Cu2O  will  appear  in  the  glass  as  the  latter  cools.  1848. 

NOTE. — Although  this  test  is  quoted  by  Plattner — perhaps  the  best  criterion 
of  its  accuracy — it  is  passed  over,  without  mention,  in  inany  works  on  chemical 
analysis.  The  writer  may  therefore  be  allowed  to  call  to  mind,  in  proof  of  its 
efficacy,  that  by  its  use  in  1848  he  pointed  out  the  presence  of  FeO  in  the 
mineral  staurolite  ("  Chem.  Gaz.,"  July  15,  1848;  see  also  Erdmann's  "Journal 
fur  pract.  Chem.,"  XLVL,  p.  119),  nearly  thirteen  years  before  this  fact — 
now  universally  admitted — was  discovered  and  announced  by  Rammelsberg, 
"Berichte  d.  Kongl.  preuss.  Akad.  d.  Wiss.  zu  Berlin,"  Marz,  1861. 


74  BLOWPIPE    PRACTICE. 

6.— DETECTION  OF  LEAD  IN  THE  PRESENCE  OF  BISMUTH. 
"When  lead  and  bismuth  are  present  together,  the  latter  metal  may 
be  readily  detected  by  its  known  reaction  with  phosphor-salt  in  a 
reducing  flame — antimony,  if  present,  being  first  eliminated ;  but  the 
presence  of  lead  is  less  easily  ascertained.  If  the  latter  metal  be  pre- 
sent in  large  quantity,  it  is  true,  the  metallic  globule  will  be  more  or 
less  malleable,  and  the  flame-border  will  assume  a  clear  blue  colour 
when  made  to  play  upon  its  surface,  or  on  the  sublimate  of  lead-oxide 
as  produced  on  charcoal ;  but  in  other  cases  this  reaction  becomes 
exceedingly  indefinite.  The  presence  of  lead  may  be  detected,  how- 
ever, by  the  following  plan,  based  on  the  known  reduction  and 
precipitation  of  salts  of  bismuth  by  metallic  lead,  a  method  which  suc- 
ceeds perfectly  with  brittle  alloys  containing  from  85  to  90  per  cent, 
of  bismuth.  A  small  crystal  or  fragment  of  nitrate  of  bismuth  is 
placed  in  a  porcelain  capsule,  and  moistened  with  a  few  drops  of  water, 
the  greater  part  of  which  is  afterwards  poured  off;  and  the  metallic 
globule  of  the  mixed  metals,  as  obtained  by  the  blowpipe,  having  been 
slightly  flattened  on  the  anvil  until  it  begins  to  crack  at  the  sides,  is 
then  placed  in  the  midst  of  the  sub-salt  of  bismuth  formed  by  the 
action  of  the  water.  In  the  course  of  a  minute  or  even  less,  according 
to  the  amount  of  lead  that  may  be  present,  an  arborescent  crystalliza- 
tion of  metallic  bismuth  will  be  formed  around  the  globule.  The 
reaction  is  not  affected  by  copper;  but  a  precipitation  of  bismuth 
would  ensue,  in  the  absence  of  lead,  if  either  zinc  or  iron  were  present. 
These  metals,  however,  may  be  eliminated  from  the  test-globule  by 
exposing  this  on  charcoal  for  some  minutes,  with  a  mixture  of  carb. 
soda  and  borax  to  a  reducing  flame.  The  zinc  becomes  volatilized, 
and  the  iron  is  gradually  taken  up  by  the  borax.  If  a  single  opera- 
tion do  not  effect  this,  the  globule  must  be  removed  from  the  saturated 
dai-k  green  glass,  and  treated  with  further  portions  of  the  mixture, 
until  the  resulting  glass  be  no  longer  coloured.  1848. 

7.— DETECTION  OF  LITHIA  IN  THE  PRESENCE  OF  SODA. 
This  test  may  be  applied  to  mixtures  of  these  alkalies  in  the  simple 
state,  or  to  their  carbonates,  sulphates,  nitrates,  or  other  compounds 
capable  of  being  decomposed  by  fusion  with  chloride  of  barium.  The 
test-substance,  in  powder,  is  to  be  mixed  with  about  twice  its  volume 
of  chloride  of  barium,  and  a  small  portion  of  the  mixture  is  to  be 


APPENDIX. 

exposed  on  a  loop  of  platinum  wire  to  the  point  of  a 
oxidating  flame.  A  deep  yellow  coloration  of  the  flame-L^  ~™  ^.«™ 
duced  by  the  volatilization  of  chloride  of  sodium,  at  first  e&sqjkKf  1^ 
This  gradually  diminishes  in  intensity,  and  after  a  short  time  a  thin 
green  streak,  occasioned  by  chloride  of  barium,  is  seen  to  stream  from 
the  point  of  the  wire,  as  the  test- matter  shrinks  further  down  into  the 
loop.  On  the  fused  mass  being  then  brought  somewhat  deeper  into 
the  flame,  the  point  and  edge  of  the  latter  will  at  once  assume  the  rich 
crimson  tinge  characteristic  of  the  presence  of  lithium  compounds ; 
and  the  colour  will  endure  sufficiently  long  to  prevent  the  slightest 
chance  of  misconception  or  uncertainty.  The  presence  of  strontium 
compounds  does  not  affect  this  reaction,  as  these  compounds,  when 
fused  with  chloride  of  barium,  cease  to  impart  a  red  colour  to  the 
flame.  (See  No.  4.)  In  order,  however,  to  ensure  success  in  the 
application  of  this  test,  it  is  necessary,  in  some  cases,  to  keep  up  a 
clear  and  sharply-defined  flame  for  about  a  couple  of  minutes.  If  the 
red  coloration  do  not  appear  by  that  time,  the  absence  of  lithia  — 
unless  the  latter  substance  be  present  in  minute  traces  only — may  be 
safely  concluded.  1850. 

8.— ACTION  OF  BARYTA  ON  TITANIC  ACID. 

Fused  with  borax  in  a  reducing  flame,  titanic  acid,  it  is  well  known, 
forms  a  dark  amethystine-blue  glass,  which  becomes  light  blue  and 
opaque  when  subjected  to  the  flaming  process.  The  amethystine 
colour  arises  from  the  presence  of  Ti*O8  •  the  light  blue  enamelled  sur- 
face, from  the  precipitation  of  a  certain  portion  of  TiO2.  The  presence 
of  baryta,  even  in  comparatively  small  quantity,  quite  destroys  the 
latter  reaction.  When  exposed  to  an  intermittent  flame,  the  glass  (on 
the  addition  of  baryta)  remains  dark  blue,  no  precipitation  of  titanic 
acid  taking  place.  Strontia  acts  in  the  same  manner,  but  a  much 
larger  quantity  is  required  to  produce  the  reaction.  1852. 

9.— DETECTION  OF  OXIDE  OF  MANGANESE  WHE>I  PRESENT 
IN  MINUTE  QUANTITY  IN  MINERAL  BODIES. 

It  is  usually  stated  in  works,  on  the  blowpipe,  that  the  smallest 
traces  of  manganese  may  be  readily  detected  by  fusion  with  carbonate 
of  soda,  or  with  a  mixture  of  carbonate  of  soda  and  nitrate  of  potash  : 
but  this  statement  is  to  some  extent  erroneous.  In  the  presence  of 
much  lime,  magnesia,  alumina,  sesquioxide  of  iron,  or  other  bodies, 


76  BLOWPIPE    PRACTICE. 

insoluble,  or  of  difficult  solubility,  in  carbonate  of  soda,  traces  of  oxide 
of  manganese  may  easily  escape  detection.  By  adding,  however,  a 
small  portion  of  borax  or  phosphor-salt  to  the  carbonate  of  soda,  these 
bodies  become  dissolved,  and  the  formation  of  a  "  turquoise  enamel " 
(manganate  of  soda)  is  readily  effected.  The  process  may  be  varied 
by  dissolving  the  test-substance  first  in  borax  or  phosphor-salt,  and 
then  treating  the  fused  bead  with  carbonate  of  soda  :  the  latter  being, 
of  course,  added  in  excess.  By  this  treatment,  without  the  addition 
of  nitrate  of  potash,  the  faintest  traces  of  oxide  of  manganese  in  lime- 
stone and  other  rocks,  are  at  once  made  known.  1852. 

NOTE. — This  method  of  examining  bodies  for  the  presence  of  manganese, 
was  recommended  by  Dr.  Leop.  IL  Fischer  in  1861  ("Leonh.  Jahrbuch " 
[1861],  p.  653),  but  the  writer  had  forestalled  him  by  nine  years,  having  already 
described  it  in  1852. 

10.— THE  COAL  ASSAY. 

In  the  practical  examination  of  coals,  the  following  operations  are 
essentially  necessary:*  (1)  The  estimation  of  the  water  or  hygro- 

*  To  these  might  be  added,  the  determination  of  the  heating  powers  or  "  absolute  warmth  ' 
of  the  coal,  but  this  may  always  be  estimated  with  sufficient  exactness  for  practical  purposes 
by  the  amount  of  eoke,  ash,  and  moisture,  as  compared  with  other  coals.  Properly  considered, 
the  litharge  test,  resorted  to  for  the  determination  of  the  calorific  power  of  coals,  is  of  very 
little  actual  value.  The  respective  results  furnished  by  good  wood  charcoal  and  ordinary  coke, 
for  example,  are  closely  alike,  if  not  in  favour  of  the  charcoal ;  and  yet  experience  abundantly 
proves  the  stronger  heating  powers  of  the  eoke.  In  practice,  moreover,  the  actual  value  of  a 
coal  does  not  always  depend  upon  the  "  absolute  warmth"  of  the  latter,  as  certain  coals,  such 
as  brown  coals  rich  in  bitumen,  may  posses*  heating  powers  of  considerable  amount  (as  esti- 
mated by  the  reduction  of  litharge)  though  only  of  brief  duration.  Thus,  the  lignites  of  the 
department  of  the  Basses  Alpes  ia  south-eastern  France,  and  those  of  Cuba,  yield  with  litharge 
from  25  to  26  parts  of  reduced  lead ;  whilst  many  caking  coals,  practically  of  much  higher  heat- 
ing power,  yield  scarcely  a  larger  amount.  When  pyrites  also  is  present  in  the  coal — a  condition 
of  very  common  occurrence — the  litharge  test  becomes  again  unsatisfactory,  the  pyrites  exerting 
a  reducing  action  on  the  lead  compound. 

As  described,  however,  by  Bruno  Kerl,  in  quoting  the  writer's  coal  assay  ("  Lothrohr-Unter- 
suchungen.-"  Zweite  Aufl.  1862,  p.  146)  the  so-called  absolute  warmth  or  heating  power  of  a  coal 
sample  may  be  determined,  if  desired,  in  blowpipe  practice,  by  the  following  modification  of 
Berthier's  method:  20  milligrammes  of  the  coal,  in  fine  powder,  are  to  be  mixed  intimately 
with  500  milligrammes  of  oxy-chloride  of  lead  (consisting  of  three  parts  of  litharge  +  1  part  of 
chloride  of  lead,  fused  together  and  finely  pulverized).  The  mixture  is  to  be  placed  in  a  blow- 
pipe crucible,  and  covered  with  about  an  equal'araount  of  the  lead  compound,  a  second  cover 
of  3  blowpipe-spoonfuls  of  powdered  glass  + 1  ipoonful  of  borax  being  spread  over  this.  The 
crucible,  covered  with  a  clay  capsule,  is  then  to  be  fitted  into  a  charcoal  block  in  the  ordinary 
blowpipe  furnace,  over  which  a  charcoal  lid  is  placed,  and  the  flame  directed  against  its  under 
«ide,  so  as  to  keep  it  at  a  red  heat  for  from  5  to  8  minutes.  The  weight  of  the  reduced  lead 
divided  by  20  gives  the  amount  of  the  lead  mixture  reduced  by  one  part  of  the  coal.  One  part 
of  pure  carbon  reduces  34  parts  of  this  mixture ;  one  part  of  charcoal,  30  to  33  parts ;  one  part 
of  bituminous  coal,  19  to  33 ;  one  part  of  brown  eoal,  H  to  26 ;  one  part  of  peat,  8  to  27  ;  and 
one  part  of  wood,  12  to  15  parts. 


APPENDIX.  77 

metric  moisture  present  in  the  coal ;  (2)  the  determination  of  the 
weight  and  character  of  the  coke ;  (3)  the  estimation  and  examination 
of  the  ash  or  inorganic  matters ;  and  (4)  the  estimation  of  the  sul- 
phur, chiefly  present  in  the  coal  as  FeS2. 

Estimation  of  Moisture. — This  operation  is  one  of  extreme  sim- 
plicity. Some  slight  care,  however,  is  required  to  prevent  other 
volatile  matters  from  being  driven  off  during  the  expulsion  of  the 
moisture.  Seven  or  eight  small  particles,  averaging  together  from 
100  to  150  milligrammes,  are  to  be  detached  from  the  assay  specimen 
by  means  of  the  cutting  pliers,  and  carefully  weighed.  They  are  then 
to  be  transferred  to  a  porcelain  capsule  with  thick  bottom,  and  strongly 
heated  for  four  or  five  minutes  on  the  support  attached  to  the  blow- 
pipe-lamp, the  unaided  flame  of  the  lamp  being  alone  employed  for 
this  purpose.  It  is  advisable  to  place  in  the  capsule,  at  the  same  time, 
a  small  strip  of  filtering  or  white  blotting-paper,  the  charring  of  which 
will  give  indications  of  the  temperature  becoming  too  high.  The  coal, 
whilst  still  warm,  is  then  to  be  transferred  to  the  little  brass  capsule 
in  which  the  weighings  are  performed,  and  its  weight  ascertained.  In 
transferring  the  coal  from  one  vessel  to  the  other,  the  larger  pieces 
should  be  removed  by  a  pair  of  fine  brass  forceps,  and  the  little  parti- 
cles or  dust  afterwards  swept  into  the  weighing  capsule  by  means  of 
the  camel's-hair  pencil  or  small  colour-brush  belonging  to  the  balance 
case.  The  weighing  capsule  should  also  be  placed  in  the  centre  of  a 
half  sheet  of  glazed  writing-paper,  to  prevent  the  risk  of  any  acci- 
dental loss  during  the  transference.  After  the  weighing,  the  opera- 
tion must  always  be  repeated,  to  ensure  that  no  further  loss  of  weight 
occur.  In  place  of  the  blowpipe-lamp,  the  spirit-lamp  may  be  employed 
for  this  operation ;  but,  with  the  former,  there  is  less  danger  of  the 
heat  becoming  too  high.  By  holding  a  slip  of  glass  for  an  instant, 
every  now  and  then,  over  the  capsule,  it  will  soon  be  seen  when  the 
moisture  ceases  to  be  given  off.  It  should  be  remarked  that  some 
anthracites  decrepitate  slightly  when  thus  treated,  in  which  case  the 
|K)rcelain  capsule  must  be  covered  at  first  with  a  small  watch-glass. 

In  good  samples  of  coal,  the  moisture  ought  not  to  exceed  3  or  4  per 
cent.,  but  in  coals  that  have  been  long  exposed  to  damp  it  is  often  as 
high  as  6  or  7,  and  even  reaches  1 5  or  20  per  cent,  in  certain  lignites. 
Where  large  quantities  of  coal  are  consumed,  therefore,  a  serious  loss  is 


78  BLOWPIPE    PRACTICE. 

entailed  on  the  purchaser  unless  the  moisture  be  properly  determined 
and  allowed  for. 

Estimation,  <&c.,  of  Coke. — In  this  operation,  a  small  crucible  of 
platinum  is  most  conveniently  employed.  The  crucible  may  consist 
of  a  coaple  of  rather  deep  spoons — the  larger  one  without  a  handle, 
so  as  to  admit  of  being  placed  over  the  smaller  spoon, 
thus  serving  as  a  lid.  The  long  handle  of  the  cru- 
cible-spoon must  be  bent  as  shewn  in  the  annexed 
figure,  in  order  that  the  spoon  may  retain  an  upright 
position  when  placed  on  the  pan  of  the  balance. 
About  150  milligrammes  of  coal  are  detached  as  before,  in  several 
small  fragments,  from  the  assay-specimen.  These  may  be  weighed 
directly  in  the  crucible,  the  latter  being  placed  in  the  little  weighing 
capsule  of  horn  or  brass,  with  its  handle-support  projecting  over  the 
side  of  this.  The  crucible,  with  its  cover  on,  is  then  taken  up  by  a 
pair  of  spring  forceps,  and  is  brought  gradually  before  the  blowpipe 
to  a  red  heat.  The  escaping  gases  will  take  fire  and  burn  for  a  few 
seconds  around  the  vessel,  and  a  small  amount  of  carbonaceous  matter 
may  be  deposited  upon  the  cover.  This  rapidly  burns  off,  however, 
on  the  heat  being  continued.  As  soon  as  it  disappears,  the  crucible 
is  to  be  withdrawn  from  the  flame,  and  placed  on  the  blowpipe-anvil 
to  cool  quickly.  Its  weight  is  then  ascertained,  always  without  remov- 
ing the  cover.  The  loss,  minus  the  weight  of  moisture  as  found  by 
the  first  process,  gives  the  amount  of  volatile  or  gaseous  matter.  The 
residue  is  the  coke  and  its  contained  ash.  The  coke  in  some  anthra- 
cites exceeds  89  or  90  per  cent.  In  anthracitic  or  dry  coals  it  usually 
varies  from  70  to  80  per  cent.,  and  the  fragments  are  sometimes  slightly 
agglutinated.  In  ordinary  bituminous  or  caking  coals,  it  amounts  in 
general  to  about  65  or  70  per  cent.,  and  presents  a  fused  and  mamil- 
lated  surface.  In  cannel  or  gas  coals,  the  percentage  of  coke  may  be 
assumed  to  equal  50  or  60,  but  it  is  sometimes  as  low  as  30.  The  coke 
fragments  are  often  partially  agglutinated,  but  they  never  present  a 
fused,  globular  aspect.  Finally,  in  lignites  or  brown  coals,  the  coke 
may  vary  from  25  to  50  per  cent.  It  forms  sharp-edged  fragments 
of  a  dull  charcoal-like  appearance,  without  any  sign  of  fusion. 

Estimation  of  Ash  or  Inorganic  Matters. — A  platinum  capsule  is 
employed  for  this  operation.  One  of  about  half  an  inch  in  diameter, 
with  a  short  ear  or  handle,  is  sufficiently  large.  A  somewhat  smaller 


APPENDIX.  79 

capsule,  with  its  handle  cut  off,  may  be  fitted  into  this  (in  reversed 
position)  to  serve  as  a  lid.  The  coal  must  be  reduced  to  a  coarse 
powder,  and  about  150  milligrammes  weighed  out  for  the  experiment. 
The  platinum  capsule  is  then  to  be  fixed  in  a  slightly-inclined  posi- 
tion above  the  spirit-lamp,  and  heated  as  strongly  as  possible.  If  the 
wick  of  the  spirit-lamp  be  raised  sufficiently,  and  the  capsule  be  light 
and  thin,  the  temperature  will  be  sufficient  to  burn  off  the  carbon,  at 
least  in  the  majority  of  cases.  The  lid  of  the  capsule  must  be  placed 
above  the  coal  powder  until  combustion  cease,  and  the  more  gaseous 
products  are  driven  off,  as  otherwise  a  portion  of  the  powder  might 
very  easily  be  lost.  During  the  after  combustion  the  powder  must 
be  gently  stirred,  and  if  agglutination  take  place  the  particles  must 
be  carefully  broken  up  by  a  light  steel  spatula,  or  by  a  piece  of  stout 
platinum  wire  flattened  at  one  end.  If  the  carbonaceous  matter  be 
not  burnt  off  by  this  treatment,  the  blowpipe  may  be  used  to  accelerate 
the  process ;  but  the  operator  must  blow  cautiously,  and  direct  the 
flame  only  against  the  under  side  of  the  capsule,  in  order  to  avoid 
the  risk  of  loss.  Finally,  on  the  ash  ceasing  to  exhibit  in  any  of 
its  particles  a  black  colour,  the  lid  of  the  capsule  is  to  be  carefully 
replaced,  and  the  whole  cooled  and  weighed.* 

In  good  coals,  the  amount  of  ash  is  often  under  2  per  cent.,  and  it 
rarely  exceeds  4  or  5  per  cent.  In  coals  of  inferior  quality,  however, 
it  may  vary  from  8  or  10  to  even  30  per  cent.  As  regards  its  compo- 
sition, the  ash  may  be — (1)  argillaceous,  consisting  essentially  of  a 
silicate  of  alumina ;  (2)  argillo-ferruginous  ;  (3)  calcareous  ;  and  (4) 
calcareo-ferruginous.  If  free  from  iron,  it  will  be  white  or  pale  gray  ; 
but  if  more  or  less  ferruginous,  it  will  present  a  red,  brown,  or  yellowish 
colour.  Phosphor-salt,  so  useful  in  general  cases  for  the  detection  of 
siliceous  compounds,  cannot  be  safely  used  to  distinguish  the  nature 
of  the  ash  obtained  in  blowpipe  assays.  Owing  to  their  fine  state  of 
division  and  to  the  small  quantity  at  command,  argillaceous  ashes  dis- 
solve in  this  reagent  with  as  much  facility  as  those  of  a  calcareous 
nature,  and  without  producing  a  characteristic  silica  skeleton,  or 
causing  the  opalization  of  the  glass.  With  calcareous  ashes  also,  the 

*  If  the  ash  be  very  ferruginous— in  which  case  it  will  present  a  red  or  tawny  colour— the 
results,  as  thus  obtained,  will  require  correction,  the  original  iron  pyrites  of  the  coal  being 
weighed  as  sesquioxide  of  iron.  In  ordinary  assays,  however— as  distinguished  from  analyses— 
this  may  be  fairly  neglected.  When  also  the  ash  happens  to  be  calcareous  and  to  occur  in  large 
quantity,  it  should  be  moistened  with  a  drop  or  two  of  a  solution  of  carbonate  of  ammonia,  and 
gently  heated,  previous  to  being  weighed. 


80  BLOWPIPE    PRACTICE. 

amount  obtained  is  rarely  sufficient  to  saturate  even  an  exceedingly- 
minute  bead  of  phosphor-salt  or  borax,  and  hence  no  opacity  is  pro- 
duced by  the  flaming  process.  The  one  kind  of  ash  may  be  distin- 
guished, nevertheless,  from  the  other,  by  moistening  it,  and  placing 
the  moistened  mass  on  reddened  litmus  paper.  Calcareous  ashes 
always  contain  a  certain  amount  of  caustic  lime,  and  thus  restore  the 
blue  colour  of  the  paper.  The  calcareous  ashes,  also,  though  princi- 
pally composed  of  carbonate  of  lime,  sometimes  contain  small  portions 
of  phosphate  and  sulphate  of  lime.  The  presence  of  the  latter  may 
be  readily  detected  by  the  well-known  production  of  an  alkaline  sul- 
phide by  fusion  with  carbonate  of  soda  in  a  reducing  flame — the  fused 
mass  exhibiting  a  reddish  colour,  and  imparting  when  moistened  a  dark 
stain  to  a  plate  of  silver  or  piece  of  lead  test-paper.  The  latter  may 
be  replaced  by  a  glazed  visiting-card.  In  examining  earthy  sulphates 
by  this  method,  a  little  borax  ought  always  to  be  added  to  the  car- 
bonate of  soda,  in  order  to  promote  the  solution  of  the  test-matter. 
If  oxide  of  manganese  be  present  in  the  ash,  the  well-known  man- 
ganate  of  soda,  or  "  turquoise  enamel,"  will  also  be  obtained  by  this 
treatment. 

Estimation  of  Sulphur. — The  following  plan  is  perhaps  the  most 
simple  that  can  be  employed  for  the  determination  of  sulphur  in  coal 
samples.  It  is  merely  an  adaptation  to  blowpipe  practice  of  the  pro- 
cess very  generally  employed  for  that  purpose  ; 

As  large  an  amount  of  coal  as  practicable,  several  pounds  at  least, 
taken  from  different  parts  of  the  same  heap  or  bed,  must  be  broken 
into  powder  and  well  stirred  together.  About  150  milligrammes  are 
to  be  weighed  out  for  the  assay.  This  amount  is  to  be  intimately 
mixed  with  about  450  milligrammes  of  nitrate  of  potash  and  an  equal 
quantity  of  carbonate  of  potash,  and  the  mixture,  with  a  good  cover- 
ing of  salt,  is  to  be  fused  in  a  small  platinum  crucible  of  about  a 
quarter  of  an  ounce  capacity.  The  crucible  may  be  fixed  in  an 
ordinary  blowpipe-furnace,  in  the  centre  of  an  already  used  charcoal- 
block,  as  the  cavity  of  the  latter  will  require  to  be  larger  than  usual ; 
or  it  may  be  ignited  by  the  flame  of  a  Bunsen  burner,  without  the 
aid  of  the  blowpipe.  The  heat  at  first  must  be  very  moderate,  as 
the  mixture  swells  up  greatly ;  but  after  a  couple  of  minutes,  or 
thereabouts,  a  tolerably  strong  blast  may  be  kept  up  for  from  two  to 
three  minutes  in  addition,  when  the  operation  will  be  finished.  The 


APPENDIX.  81 

alkalino  sulphate,  thus  produced,  is  dissolved  out  by  boiling  water, 
and  the  filtered  solution,  acidified  by  a  few  drops  of  hydrochloric  acid, 
is  then  treated  with  chloride  of  barium.  The  weight  of  the  pre- 
cipitate divided  by  7.28  gives  the  amount  of  sulphur.  An  ordinary 
blowpipe-crucible  of  clay  may  be  employed  for  this  operation ;  but  it 
is  always  strongly  attacked  by  the  mixture  during  fusion,  and  is 
otherwise  less  convenient  for  the  purpose  than  one  of  platinum. 

When  the  iron  pyrites  in  the  coal  is  not  in  a  state  of  semi-decom- 
position, its  amount,  and  consequently  the  amount  of  sulphur,  may 
be  arrived  at  far  more  nearly  than  might  at  first  thought  be  supposed, 
by  the  simple  process  of  washing  in  the  agate  mortar.  Each  single 
part  of  pyrites  corresponds  to  0.533  of  sulphur.  Some  large  pieces 
of  the  assay-coal  should  be  selected,  and  broken  up  into  powder ;  and 
on  this,  several  trials  must  be  made.  About  500  milligrammes  may 
be  taken  for  each  trial,  and  washed  in  three  or  four  portions.  In 
the  hands  of  one  accustomed  to  the  use  of  the  mortar  in  reducing 
experiments,  the  results,  owing  to  the  lightness  of  the  coal  particles, 
and  the  consequent  ease  with  which  they  are  floated  off,  come  out 
surprisingly 'near  to  the  truth.  In  travelling,  we  may  dispense  with 
the  washing  bottle,  by  employing,  in  its  place,  a  piece  of  straight 
tubing  drawn  out  abruptly  to  a  point.  This  is  to  be  tilled  by  suction, 
and  the  water  expelled  with  the  necessary  force  by  blowing  down  the 
tube.  A  tube  6  inches  long  and  the  fourth  of  an  inch  in  diameter 
will  hold  more  than  a  sufficient  quantity  of  water  to  be  used  between 
the  separate  grindings.  The  mortar  should  be  but  slightly  inclined, 
and  the  stream  of  water  must  not  be  too  strong  :  otherwise,  especially 
if  the  coal  be  ground  up  very  fine,  portions  of  the  pyrites  may  be 
lost.  The  proper  manipulation,  however,  is  easily  acquired  by  a 
little  practice.  1858. 

11.— PHOSPHORUS  IN  IRON  WIRE. 

Many  years  ago,  it  was  stated  by  GRIFFIN  that  thin  iron  wire 
exhibits,  in  burning,  a  green  light.  This  statement  is  repeated  by 
Prof.  GALLOWAY  in  various  editions  of  his  useful  little  work  on 
chemical  analysis  :  iron  wire  being  placed  in  one  of  the  tables,  given 
in  that  manual,  among  the  substances  which  impart  a  green  colora- 
tion to  the  blowpipe-name.  On  the  other  hand,  neither  BERZELIUS, 
PLATTNER,  RICHTER,  VON  KOBELL,  DR.  HARALD  LENZ  (Die 
7 


82  BLOWPIPE    PRACTICE. 

Lothrohrschule,  1848J,  SCHEERER,  BRUNO  KEEL,  nor  any  other  of 
the  numerous  workers  with  the  blowpipe  on  the  continent  of  Europe 
have  ever  alluded  to  the  reaction.  LENZ  gives  a  minute  description 
of  the  action  of  the  blowpipe-flame  on  iron  wire,  and  points  out  that 
the  fusion  is  always  accompanied  by  oxidation ;  but  he  makes  no 
allusion  to  any  coloration  of  the  flame.  Struck  by  this  apparent 
omission,  I  have  examined  a  number  of  samples  of  iron  wire  by  the 
blowpipe.  All  the  light-coloured  and  comparatively  hard  wires 
exhibited  the  reaction  very  distinctly.  A  bright  green  flame  streamed 
from  the  point  of  the  wire  during  the  oxidation  and  fusion  of  the 
latter,  and  a  rapid  scintillation  or  emission  of  sparks  accompanied 
the  phenomenon.  On  the  other  hand,  the  soft  and  dark  wires  fused 
much  less  readily,  and  did  not  occasion  the  slightest  coloration  of  the 
flame.  The  green  flame-coloration,  occasioned  by  the  harder  wires, 
arises,  I  find,  from  the  presence  of  a  minute  amount  of  phosphorus, 
this  being  converted  into  phosphoric  acid  during  the  combustion  of 
the  wire.  As  iron-wire  is  often  employed  in  blowpipe  practice  as  a 
reagent  for  phosphoric  acid  in  phosphates,  and  as  it  is  also  occasion- 
ally used  in  preparing  a  solution  of  iron  oxide  (Fe2O3)  for  the  estima- 
tion of  phosphoric  acid  in  bodies  generally,  the  publication  of  the 
present  note  may  not  be  altogether  superfluous.  1864. 

12.— DETECTION  OF  MINUTE  TRACES  OF  COPPER  IN  IRON 
PYRITES  AND  OTHER  BODIES. 

Although  an  exceedingly  small  percentage  of  copper  may  be  detected 
in  blowpipe  experiments  by  the  reducing  process,  as  well  as  by  the 
azure-blue  coloration  of  the  flame  when  the  test-matter  is  moistened 
with  hydrochloric  acid,  these  methods  fail  in  certain  extreme  cases  to 
give  satisfactory  results.  It  often  happens  that  veins  of  iron  pyrites 
lead  at  greater  depths  to  copper  pyrites.  In  this  case,  according  to 
the  experience  of  .the  writer,  the  iron  pyrites  will  almost  invariably 
hold  minute  traces  of  copper.  Hence  the  desirability,  in  exploring 
expeditions  more  especially,  of  some  ready  test,  by  which,  without 
the  necessity  of  employing  acids  or  other  bulky  and  difficultly  portable 
reagents,  these  traces  of  copper  may  be  detected.  The  following- 
simple  method  will  be  found  to  answer  the  purpose:  The  test-sub- 
stance, in  powder,  must  first  be  roasted  on  charcoal,  or,  better,  on  a 


APPENDIX.  83 

fragment  of  porcelain,*  in  order  to  drive  off  the  sulphur.  A  small 
portion  of  the  roasted  ore  is  then  to  be  fused  on  platinum  wire  with 
phosphor-salt ;  and  some  bisulphate  of  potash  is  to  be  added  to  the 
glass  (without  this  being  removed  from  the  wire)  in  two  or  three  suc- 
cessive portions,  or  until  the  glass  becomes  more  or  less  saturated. 
This  effected,  the  bead  is  to  be  shaken  oft'  the  platinum  loop  into  a 
small  capsule,  and  treated  with  boiling  water,  by  which  either  the 
whole  or  the  greater  part  will  be  dissolved  ;  and  the  solution  is  finally 
to  be  tested  with  a  small  fragment  of  ferrocyaiiid  of  potassium 
("  yellow  prussiate.")  If  copper  be  present  in  more  than  traces,  this 
reagent,  it  is  well  known,  will  produce  a  deep  red  precipitate.  If  the 
copper  be  present  in  smaller  quantity,  that  is,  in  exceedingly  minute 
traces,  the  precipitate  will  be  brown  or  brownish-black  ;  and  if  copper 
be  entirely  absent,  the  precipitate  will  be  blue  or  green — assuming, 
of  course,  that  iron  pyrites  or  some  other  ferruginous  substance  is 
operated  upon.  In.  this  experiment,  the  preliminary  fusion  with 
phosphor-salt  greatly  facilitates  the  after  solution  of  the  substance  in 
bisulphate  of  potash.  In  some  instances,  indeed,  no  solution  takes  place 
if  this  preliminary  treatment  with  phosphor-salt  be  omitted.  1865. 

13.— DETECTION  OF  ANTIMONY  IN  TUBE-SUBLIMATES. 
In  the  examination  of  mineral  bodies  for  antimony,  the  test-sub- 
stance is  often  roasted  in  an  open  tuba  for  the  production  of  a  white 
sublimate.  The  presence  of  antimony  in  this  sublimate  may  be 
detected  by  the  following  process — a  method  more  especially  availably 
when  the  operator  has  only  a  portable  blowpipe-case  at  his  command.. 
The  portion  of  the  tube  to  which  the  chief  portion  of  the  sublimate  is 
attached  is  to  be  cut  off  by  a  triangular  file,  and  dropped  into  a  test- 
tube  containing  some  tartaric  acid  dissolved  in  water.  This  being 
warmed  or  gently  boiled,  a  part  at  least  of  the  sublimate  will  be  dis- 
solved. Some  bisulphate  of  potash — either  alone,  or  mixed  with  some 
carb.  soda  and  a  little  borax,  the  latter  to  prevent  absorption — is  then, 

*  In  the  roasting  of  metallic  sulphides,  &c.,  the  writer  has  employed,  for  some  years,  small 
fragments  of  Berlin  or  Meissen  porcelain,  such  as  result  from,  the  breakage  of  crucibles  and 
other  vessels  of  that  material.  The  test-substance  is  crushed  to  po\yd.er,  moist,ened  slightly, 
and  spread  over  the  surface  of  the  porcelain  ;  and  when  the  operation  is  finished,-  tke,  powder  is 
eisily  scraped  off  by  the  point  of  a  knife-blade  or  small  &teel-spat,ula.  In  roasting  operations, 
rarely  more  than  a  dull  red  heat  is  required ;  but  these  porcelain  fragments  may  be  rendered 
white-hot,  if  such  be  necessary,  without  risk  of  fracture.  They  are  held,  most  conveniently,  by 
a.  pair  of  spring-forceps.— "Canadian  Journal,"  September,  I860. 


84  BLOWPIPE   PRACTICE. 

to  be  fused  on  charcoal  in  a  reducing  flame ;  and  the  alkaline  sulphide, 
thus  produced,  is  bo  be  removed  by  the  point  of  a  knife-blade,  and 
placed  in  a  small  porcelain  capsule.  The  hepatic  mass  is  most  easily 
separated  from  the  charcoal  by  removing  it  before  it  has  time  to  soli- 
dify. Some  of  the  tartaric  acid  solution  is  then  to  be  dropped  upon 
it,  when  the  well-known  orange-coloured  precipitate  of  Sb2S3  will  at 
once  result. 

In  performing  this  test,  it  is  as  well  to  employ  a  somewhat  large 
fragment  of  the  test-substance,  so  as  to  obtain  a  thick  deposit  in  the 
tube.  It  is  advisable  also  to  hold  the  tube  in  not  too  inclined  a  posi- 
tion in  order  to  let  but  a  moderate  current  of  air  pass  through  it ; 
and  care  must  be  taken  not  to  expose  the  sublimate  to  the  action  of 
the  flame — otherwise  it  might  be  converted  almost  wholly  into  a  com- 
pound of  Sb2O3  and  Sb'2O5,  the  greater  part  of  which  would  remain 
undissolved  in  the  tartaric  acid  solution.  A  sublimate  of  arbenious 
acid,  treated  in  this  manner,  would,  of  course,  yield  a  yellow  precipi- 
tate, easily  distinguished  by  its  colour,  however,  from  the  deep  orange 
antimonial  sulphide.  The  crystalline  character,  etc.,  of  the  sublimate, 
would  also  effectually  prevent  any  chance  of  misconception. 

14.— ON  THE  REACTIONS  OF  METALLIC  THALLIUM  BEFORE 
THE  BLOWPIPE. 

The  following  reactions  are  given  from  direct  experiments  by  the 
writer :  * 

In  the  closed  tube,  thallium  melts  easily,  and  a  brownish-red 
vitreous  slag,  which  becomes  pale  yellow  on  cooling,  forms  around 
the  fused  globule. 

In  the  open  tube,  fusion  also  takes  place  on  the  first  application  of 
the  flame,  whilst  the  glass  becomes  strongly  attacked  by  the  formation 
of  a  vitreous  slag,  as  in  the  closed  tube.  Only  a  small  amount  of 

*The  reactions  given  by  Crookes  are  as  follows:  "The  metal  melts  instantly  on  charcoal, 
and  evolves  copious  brown  fumes.  If  the  bead  is  heated  to  redness,  it  glows  for  some  time  after 
the  source  of  heat  is  removed,  continually  evolving  vapours  which  appear  to  be  a  mixture  of 
metal  and  oxide.  A  reddish  amorphous  sublimate  of  proto-peroxide  surrounds  the  fused 
globule.  When  thallium  is  heated  in  an  open  glass  tube,  it  melts  and  becomes  rapidly  con- 
verted into  the  more  fusible  protoxide,  which  strongly  attacks  the  glass.  This  oxide  is  of  a 
dark  red  colour  when  hot,  solidifying  to  a  brown  crystalline  mass.  The  fused  oxide  attacks 
glass  and  porcelain,  removing  the  silica.  Anhydrous  peroxide  of  thallium  is  a  brown  powder, 
fusing  with  difficulty  and  evolving  oxygen  at  a  red  heat,  becoming  reduced  to  the  protoxide. 
The  phosphate  and  sulphate  will  stand  a  red  Ueat  without  change." 


APPENDIX.  85 

sublimate  is  produced.  This  is  of  a  grayish- white  colour,  but  under 
the  magnifying-glass  it  shews  in  places  a  faint  iridescence. 

On  charcoal,  per  se,  thallium  melts  very  easily,  and  volatilizes  in 
dense  fumes  of  a  white  colour,  streaked  with  brown,  whilst  it  imparts 
at  the  same  time  a  vivid  emerald-green  coloration  to  the  point  and 
edge  of  the  flame.  If  the  heat  be  discontinued,  the  fused  globule  con- 
tinues to  give  off  copious  fumes,  but  this  action  ceases  at  once  if  the 
globule  be  removed  from  the  charcoal.  A  deposit,  partly  white  and 
partly  dark  brown,  of  oxide  and  teroxide  is  formed  on  the  support ; 
but,  compared  with  the  copious  fumes  evolved  from  the  metal,  this 
deposit  is  by  no  means  abundant,  as  it  volatilizes  at  once  where  it 
comes  in  contact  with  the  glowing  charcoal.  If  touched  by  either 
flame,  it  is  dissipated  immediately,  in  imparting  a  brilliant  green 
colour  to  the  flame-border.  The  brown  deposit  is  not  readily  seen  on 
charcoal ;  but  if  the  metal  be  fused  on  a  cupel,  or  on  a  piece  of  thin 
porcelain  or  other  non-reducing  body,  the  evolved  fumes  are  almost 
wholly  of  a  brownish  colour,  and  the  deposit  is  in  great  part  brownish- 
black.  It  would  appear,  therefore,  to  consist  of  T1O3,  rather  than  of 
a  mixture  of  metal  and  oxide.  On  the  cupel,  thallium  is  readily 
oxidized  and  absorbed.  It  might  be  employed,  consequently,  as 
suggested  by  Crookes,  in  place  of  lead  in  cupellation ;  but,  to  effect 
the  absorption  of  copper  or  nickel,  a  comparatively  large  quantity  is 
required.  When  fused  on  porcelain,  the  surface  of  the  support  is 
strongly  attacked  by  the  formation  of  a  silicate,  which  is  deep  red 
whilst  hot,  and  pale  yellow  on  cooling. 

The  teroxide,  as  stated  by  Crookes,  evolves  oxygen  when  heated, 
and  becomes  converted  into  T1O.  The  latter  compound  is  at  once 
reduced  on  charcoal,  and  the  reduced  metal  is  rapidly  volatilized  with 
brilliant  green  coloration  of  the  flame.  The  chloride  produces  the 
same  reaction,  by  which  the  green  flame  of  thallium  may  easily  be 
distinguished  from  the  green  copper-flaine ;  the  latter,  in  the  case  of 
cupreous  chlorides,  becoming  changed  to  azure-blue.  With  borax 
and  phosphor-salt,  thallium  oxides  form  colourless  glasses,  which 
become  gray  and  opaque  when  exposed  for  a  short  time  to  a  reducing 
flame.  With  carb.  soda,  they  dissolve  to  some  extent,  but  on  char- 
coal a  malleable  metallic  globule  is  obtained.  The  presence  of  soda, 
unless  in  great  excess,  does  not  destroy  the  green  coloration  of  the 
flame. 


86  BLOWPIPE    PRACTICE. 

Thallium  alloys  more  or  less  readily  with  most  other  metals  before 
the  blowpipe.  With  platinum,  gold,  bismuth,  and  antimony,  respec- 
tively, it  forms  a  dark-gray  brittle  globule.  With  silver,  copper,  or 
lead,  the  button  is  malleable.  With  tin,  thallium  unites  readily,  but 
the  fused  mass  immediately  begins  to  oxidize,  throwing  out  excres- 
cences of  a  dark  colour,  and  continuing  in  a  state  of  ignition  until 
the  oxidation  is  complete.  In  this,  as  in  other  reactions,  therefore, 
the  metal  much  resembles  lead.  1876. 

15.— ON  THE  OPALESCENCE  PRODUCED  BY  SILICATES  IN 
PHOSPHOR-SALT. 

It  is  well  known  that  most  silicates  when  fused  with  phosphor-salt 
are  only  partially  attacked ;  the  bases,  as  a  rule,  gradually  dissolving 
in  the  flux,  whilst  the  silica  remains  in  the  form  of  a  flocculent  mass 
technically  known  as  a  "  silica  skeleton."     Very  commonly,  almost 
invariably  indeed,  if  the  blast  be  long  continued,  the  bead  becomes 
more  or  less  milky  or  opalescent  on  cooling.    This  latter  reaction  was 
apparently  regarded  by  Plattner  as  essentially  due  to  the  presence  of 
alkaline  or  earthy  bases,  such  as  exhibit  the  reaction  per  se.    He  states, 
"  Probirkunst,"  Dritte  A  ullage,  p.  468  :  "  Da  man  nun  von  mehreren 
Silikaten  ein  Glas  bekommt,  welches,  so  lange  es  heiss  ist,  zwar  klar 
erscheint,  aber  unter  der  Abkiihlung  mehr  oder  weniger  opalisirt,  so 
muss  man  sich  von  der  ausgeschiedenen  Kieselsaure  iiberzeugen,  so 
lange  das  Glas  noch  heiss  ist,  und  dabei  die  Loupe  z'u  Hiilfe  nehmen. 
Die  so  eben  erwahnte  Erscheinting  tritt  gewohnlich  bei  solchen  Sili- 
katen  ein,  deren  Basen,  Kalkerde,  Talkerde,  Beryllerde  oder  Yttererde 
sind,  die  fur  sich  mit  Phosphorsalz,  bei  gewisser  Sattigung  des  Glases, 
unter  der  Abkiihlung  oder  durch  Flattern  milchweiss  oder  opalartig 
werden."     Dr.  Theodor  Richter,  the  editor  of  the   4th  edition  of 
Plattner's  work,  leaves  out  the  "  gewohnlich  "  of  the  above  quotation, 
a.nd  so  makes  the  implication  still  stronger.     In  this  vierte  Auflage, 
the  statement  runs  :  "  Bei  solchen  Silikaten  deren  Basen  fur  sich  mit 
Phosphorsalz,  bei  gewisser  Sattigung  des  Glases,  unter  der  Abkiih- 
lung  oder  durch  Flattern  milchweiss  oder  opalartig  werden  (Kalkerde} 
Talkerde,    Beryllerde,   oder   Yttererde)   wjrd    die   Perle  unter  der 
Abkiihlung  mehr  oder  weniger  triibe."     It  is  true  enough  that  sili- 
cates in  which  these  bases  are  present  exhibit  the  reaction }  but  as 
other  silicates,  practically  all,  indeed,  exhibit  the  reaction  also,  the 
inference  implied  in  the  above  statement  is  not  admissible.     The 


APPENDIX.  87 

opalescence  of  tlie  glass  arises  entirely  from  precipitated  silica.  If  the 
blast  be  sufficiently  kept  up,  a  certain  amount  of  silica  is  almost 
always  dissolved,  but  this  becomes  precipitated  as  the  glass  cools.  A 
simple  experiment  will  shew  that  this  is  the  true  cause  of  the  opales- 
cence. If  some  pure  silica  (or  a  silicate  of  any  kind),  in  a  powdered 
condition,  be  dissolved  before  the  blowpipe-flame  in  bora.x  until  the 
glass  be  nearly  saturated,  and  some  phosphor-salt  be  then  added,  and 
the  blowing  be  continued  for  an  instant,  a  precipitation  of  silica  will 
immediately  take  place,  the  bead  becoming  milky — or,  in  the  case  of 
many  silicates,  opaque-white — on  cooling.  This  test  may  be  resorted 
to  for  the  detection  of  silica  in  the  case  of  silicates  which  dissolve 
with  difficulty  in  phosphor-salt  alone,  or  which  do  not  give  a  well- 
pronounced  "skeleton"  with  that  reagent.*  1876. 

16.— ON  THE  REACTIONS  OF  CHROMIUM  AND  MANGANESE 
WITH  CARBONATE  OF  SODA. 

When  a  mineral  substance  is  suspected  to  contain  manganese,  it  is 
commonly  tested  by  fusion  with  carbonate  of  soda.  But  chromium 
compounds  form  with  that  reagent  a  green  or  greenish-yellow  enamel, 
much  resembling  that  formed  by  some  compounds  of  manganese. 

The  chromate-of-soda  enamel,  however,  is  yellowish-green  after 
exposure  to  an  oxidating  flame,  and  the  green  colour  never  exhibits 
any  tinge  of  blue. 

The  manganate-of-soda  enamel,  on  the  other  hand  is  generally 
greenish-blue  when  quite  cold. 

To  avoid,  however,  any  risk  of  error  in  the  determination,  the 
bead  may  be  saturated  with  vitrified  boracic  acid,  until  all  the  car- 
bonic acid  is  expelled,  and  a  clear  glass  is  obtained.  The  chrome 
glass  will  retain  its  green  colour,  whilst  the  manganese  glass  will 
become  amethystine  or  violet.  In  place  of  boracic  acid,  silica  may 


*  By  whom  was  the  formation  of  a  "  silica  skeleton"  first  made  known?  There  is  no  reference 
to  it  in  the  early  treatise  of  Von  Engestrom  attached  to  his  translation  of  Cronstedt's  "  Miner- 
alogie,"  1st  edition,  1770 ;  2nd  edition,  by  John  Hyacinth  de  Magellan,  1788),  although  phosphor- 
salt  is  mentioned  as  a  reagent  under  the  term  of  sr'l  fusibile  microcosmicnm,  and  was  indeed  used 
by  Cronstedt  before  1758,  the  year  in  which  his  "  Mineralogie  "  was  anonymously  published. 
Bergmann,  who  followed  as  a  blowpipe  worker,  states  that  "siliceous  earth  "is  very  slowly- 
attacked  by  mieroeosmie  salt,  but  lie  does  not  seem  to  have  remarked  the  skeleton  formation 
in  the  case  of  any  silicate.  The  reaction  appears  to  have  been  first  definitely  pointed  out  by 
Berzelius  in  his  staudard  work  on  the  blowpipe,  published  in  1820.  It  was  therefore  most 
probably  discovered  by  him,  or  perhaps— as  he  lays  no  claim  to  its  discovery,  whilst  claiming 
to  be  the  originator  of  other  tests— it  may  have  been  eomnmuieated  to  him  by  Gahn? 


88  BLOWPIPE    PRACTICE. 

be  used  if  more  convenient.     In  tliis  case  the  reaction  is  assisted  by 
the  addition  of  a  very  small  amount  of  borax.      1871-76. 

17.— ON  THE  DETECTION  OF  CADMIUM  IN  THE  PRESENCE  OF 
ZINC  IN  BLOWPIPE  EXPERIMENTS. 

When  cadmiferous  zinc  ores,  or  furnace-products  derived  from 
these,  are  treated  in  powder  with  carb.  soda  on  charcoal,  the  charac- 
teristic red-brown  deposit  of  cadmium  oxide  is  generally  formed  at 
the  commencement  of  the  experiment.  If  the  blowing  be  continued 
too  long,  however,  this  deposit  may  be  altogether  obscured  by  a  thick 
coating  of  zinc  oxide.  When,  therefore,  the  presence  of  cadmium  is 
suspected  in  the  assay-substance,  it  is  advisable  to  employ  the  fol- 
lowing process  for  its  detection.  The  substance,  if  in  the  metallic 
state,  must  first  be  gently  roasted  on  a  support  of  porcelain  or  other 
non-reducing  body.  Some  of  the  resulting  powder  is  then  fused  with 
borax  or  phosphor-salt  on  a  loop  of  platinum  wire,  and  bisulphate  of 
potash  in  several  successive  portions  is  added  to  the  fused  bead.  The 
latter  is  then  shaken  off  the  wire  into  a  small  porcelain  capsule,  and 
treated  with  boiling  water.  A  bead  of  alkaline  sulphide  is  next  pre- 
pared by  fusing  some  bisulphate  of  potash  on  charcoal  in  a  reducing 
flame,  and  removing  the  fused  mass  before  it  hardens.  A  portion  of 
the  solution  in  the  capsule  being  tested  with  this,  a  yellow  precipi- 
tate will  be  produced  if  cadmium  be  present.  The  precipitate  can 
be  collected  by  decantation  or  filtration,  and  tested  with  some  carb. 
soda  on  charcoal.  This  latter  operation  is  necessary,  because  if  either 
antimony  or  arsenic  were  present,  an  orange  or  yellow  precipitate 
would  also  be  produced  by  the  alkaline  sulphide.  By  treatment 
with  carb.  soda  on  charcoal,  however,  the  true  nature  of  the  precipi- 
tate would  be  at  once  made  known.  1876. 

18.— ON  THE  SOLUBILITY  OF  BISMUTH  OXIDE  IN  CARBONATE 
OF  SODA  BEFORE  THE  BLOWPIPE. 

Neither  in  the  treatise  of  Berzelius,  nor  in  the  more  modern  and 
advanced  work  of  Plattner,  is  any  reference  made  to  the  behaviour 
of  oxide  of  bismuth  with  carb.  soda  in  an  oxidating  flame.  In 
Plattner's  "  Tabellarishe  Uebersicht  des  Verhaltens  der  Alkalien, 
Erden,  und  Metalloxyde  fur  sich  und  mit  Reagentien  im  Lbthrohr- 
feuer,"  whilst  oxide  of  lead  is  stated}  correctly,  to  be  soluble  in  carb. 


APPENDIX.  89 

soda  in  an  oxidating  flame,  the  reference  to  oxide  of  bismuth  is, 
simply,  that  with  carb.  soda  on  charcoal  it  becomes  immediately 
reduced  to  metailic  bismuth;  and  none  of  his  translators  seem  to 
have  thought  it  necessary  to  supply  the  omission.  In  Hartmann's 
tabular  "  Untersuchimgen  mit  dem  Lothrohr,"  in  the  handy  little 
work  of  Bruno  Kerb  ("  Leitfaden  bei  qualitativen  und  quantitativen 
Lbthrohr-Untersuchuiigeii  "),  in  the  "  Lothrohr-Tabellen  "  of  Hirsch- 
wald,  and  all  other  blowpipe  books  that  I  have  met  with,  the  same 
singular  omission  occurs.  This  seems  to  bear  out  very  forcibly  the 
somewhat  cynical  adage  that  "  books  are  made  from  books."  To 
supply  the  omission,  it  may  be  observed  that  bismuth  oxide  dissolves 
in  carb.  soda  very  readily  in  an  oxidating  flame,  if  the  supporting 
agent  be  platinum  wire  or  other  non-reducing  body.  The  glass  is 
clear  yellow  whilst  hot,  but  on  cooling  it  assumes  an  orange  or  yel- 
lowish-brown colour,  and  becomes  pale  yellow  and  opaque  when  cold. 
As  regards  their  solubility  by  fusion  in  carb.  soda,  metallic  oxides 
fall  into  three  gtoups:  (1)  Easily  soluble,  e.g.,  PbO,  Bi'O3,  BaO,  &c.; 
(2)  Slightly  or  partially  soluble,  e.g.,  Mn'O8,  CoO,  &c.;  and  (3), 
Insoluble,  e.g.,  Fe203,  Ce'O3,  NiO,  CaO,  MgO,  &c.  1876. 

19.— ON  THE  DETECTION  OF  CARBONATES  IN  BLOWPIPE 
PRACTICE. 

A  mineral  substance  of  non-metallic  aspect,  in  nine  cases  out  of 
ten,  will  be  either  a  silicate,  sulphate,  phosphate,  borate,  carbonate, 
fluoride,  or  chloride  :  more  especially  if  the  streak  be  uncoloured  or 
merely  exhibit  some  shade  of  green  or  blue,  or  if  the  substance  evolve 
no  fumes  when  heated  on  charcoal. 

Simple  fusion  with  phosphor-salt  on  a  loop  of  platinum  wire 
serves  at  once  to  distinguish  a  silicate  from  any  of  the  other  bodies 
enumerated  above,  as,  whilst  the  silicate  is  but  slowly  attacked, 
these  other  bodies  are  readily  and  rapidly  dissolved.  Among  the 
latter,  again,  the  carbonates  are  distinguished  very  readily  by  the 
marked  effervescence  which  they  produce  in  the  bead  by  the  evolution 
of  carbonic  acid  during  fusion — the  phosphates,  sulphates,  &c.,  dis- 
solving quietly.  The  reaction  is  quite  as  distinctive  as  that  produced 
by  the  application  of  an  ordinary  acid ;  but,  of  course,  it  may  arise 
in  both  cases  not  only  from  a  carbonate  proper,  but  from  the  presence 
of  intermixed  calcite  or  other  carbonate  in  the  su  bstance  under  exami 


90  BLOWPIPE    PRACTICE. 

nation ;  and  it  is  also  occasioned  by  bodies  which  evolve  oxygen  on 
ignition;  but  these  latter,  manganese  oxides  excepted,  are  of  rare 
occurrence  among  minerals  proper.  By  this  reaction,  upwards  of 
twenty  years  ago,  the  writer  detected  the  presence  of  carbonate  of 
lime  in  certain  specimens  of  Wernerite  (the  "  Wilsonite  "  variety, 
portions  of  which  had  previously  been  analyzed  without  the  impurity 
having  been  discovered.  It  need  scarcely  be  stated  that  the  test- 
substance  must  be  added  to  the  phosphor-salt,  on  the  platinum  loop, 
only  after  the  quiet  fusion  of  the  flux  into  a  transparent  glass.  The 
reaction  is,  of  course,  manifested  equally  well  with  borax.  1871-76. 

20.— ON  THE  DETECTION  OF  BROMINE  IN  BLOWPIPE 
EXPERIMENTS. 

"When  fused  with  phosphor-salt  and  copper  oxide,  the  bromides,  it 
is  well  known,  impart  .an  azure-blue  coloration  to  the  flame,  much 
like  that  produced  by  chlorides  under  similar  treatment,  although 
streaked  more  or  less  with  green,  especially  at  the  commencement  of 
the  operation.  To  distinguish  these  bodies  more  closely,  Berzelius 
recommended  the  fusion  of  the  test-substance  with  6  or  7  volumes  of 
bisulphate  of  potash  in  a  closed  tube.  Bromides  by  this  treatment 
become  decomposed  as  a  rule,  and  give  off  strongly-smelling  brownish 
or  yellowish-red  vapours  of  bromine.  But  this  process  does  not 
always  give  satisfactory  results,  as  in  some  instances  the  bromide  is 
very  slightly  attacked.  In  this  case,  the  following  method,  based  on 
a  peculiar  reaction  of  bromide  of  silver,  first  pointed  out  by  Plattner, 
may  be  resorted  to :  If  insoluble,  the  bromide  is  fused  with  2  or  3 
volumes  of  carb.  soda.  A  soluble  bromide  of  sodium  is  thus  formed, 
with  separation  of  the  base.  To  the  filtered  or  decanted  solution 
of  the  fused  mass,  a  small  fragment  of  nitrate  of  silver  is  added,  in 
order  to  precipitate  bromide  of  silver.  This,  collected  by  decanta- 
tion,  is  fused  with  a  small  quantity  of  bisulphate  of  potash  in  a  little 
flask  or  test-tube.  The  bromide  of  silver  will  quickly  separate  from 
the  flux  in  the  form  of  a  blood-red  globule,  which  becomes  pale- 
yellow  when  cold.  The  little  globule,  washed  out  of  the  tube  by 
dissolving  the  fused  bisulphate  in  some  warm  water,  is  carefully  dried 
bv  being  rubbed  in  a  piece  of  blotting  or  filtering  paper,  and  is  then 
placed  in  the  sunlight.  After  a  short  time  it  will  turn  green.  Chlo- 
ride of  silver,  as  obtained  in  a  similar  manner,  melts  into  an  orange- 
red  globule,  which  changes  to  clear-yellow  on  cooling,  and  finally 


APPENDIX.  91 

becomes  white,  or  nearly  so.  Placed  in  sunlight,  it  rapidly  assumes 
a  dark-gray  colour.  Iodide  of  silver,  under  similar  treatment,  forms 
whilst  hot  an  almost  black  globule,  which  becomes  amethyst-red 
during  cooling,  and  dingy-yellow  when  cold.  In  the  sunlight  it 
retains  the  latter  colour.  A  mixture  of  chloride  and  iodide  of  silver 
assumes  a  greenish  tint  somewhat  resembling  the  colour  acquired  by 
the  bromide  globule.  This,  however,  can  scarcely  give  rise  to  any 
error,  as  the  presence  of  iodine  is  revealed — even  if  no  violet-coloured 
fumes  be  emitted — -by  the  dark  amethystine  colour  of  the  bead  whilst 
hot.  1876. 

21.— BLOWPIPE  REACTIONS  OF  METALLIC  ALLOYS. 
In  examining  these  reactions,  about  equal  portions  of  the  metals 
(forming  the  alloy)  may  be  placed  together,  on  charcoal,  and  subjected 
to  the  action  of  a  reducing  flame. 

1.  Platinum  and  Tin  unite  with  violent  deflagration  and  emission 
of  light,  forming  a  hard,  brittle,  and  infusible  globule. 

2.  Platinum,  Zinc  and   Tin  unite  with  violent  action,  the  zinc 
throwing  off  long  flakes  of  oxide. 

3.  Platinum  and  Zinc,  per  se,  do  not  combine,  the  zinc  burning 
into  oxide. 

4.  Platinum  and  Lead  unite  quietly,  forming  a  brittle  globule. 

5.  Platinum  and  Thallium  unite  quietly ;  the  resulting  globule  is 
dark  externally,  gray  internally,  and  quite  brittle. 

6.  Platinum  and  Bismuth  unite  quietly,  or  with  merely  slight 
spitting,  into  a  dark,  brittle  globule. 

7.  Platinum  and  Copper  combine  quietly,  though  not  very  readily, 
into  a  hard,  light-coloured,  malleable  globule. 

8.  Platinum  and  Silver  unite  quietly,  but  not  very  readily,  unless 
the  silver  be  greatly  in  excess,  into  a  white  malleable  globule. 

9.  Platinum  and  Gold  unite  quietly,  forming  (if  the  gold  be  some- 
what in  exqess)  a  yellow  malleable  globule. 

10.  Gold  and  Tin  unite  quietly  into  a  very  brittle  globule. 

1 1.  Gold  and  Zinc  do  not  combine  per  se;  the  zinc  burns  into  oxide. 

12.  Gold  and  Lead  combine  quietly,  forming  a  gray  brittle  bead. 

13.  Gold  and  Thallium  unite  quietly,  but  separate  again  to  some 
extent  during  cooling.     The  globule  may  thus  frequently  be  flattened 
out,  but  not  without  cracking  at  the  sides.     If  the  metals  remain 
united.,  the  button  is  dark  blackish -gray,  and  quite  brittle. 


92  BLOWPIPE    PRACTICE. 

14.  Gold  and  Bismuth  unite  quietly  and  readily,  forming  a  very 
brittle  globule. 

15.  Gold  and  Copper,  and  16,  Gold  and  Silver,  unite,  and  form  a 
malleable  globule. 

17.  Silver  and  Tin  unite  quietly  into  a  malleable  globule. 

18.  Silver  and  Lead  unite  readily  into  a  malleable  globule. 

19.  Silver  and  Thallium  combine  readily  :  the  globule  is  malleable. 

20.  Silver  and  Bismuth  unite  readily  and  quietly :  the  globule  is 
brittle,  but  admits  of  being  slightly  flattened  out. 

21.  Silver  and  Copper,  and  22,  Silver  and  Gold,  form  malleable 
globules.     The  gold  alloy,  even  with  gold  largely  in  excess,  is  quite 
white.     If  it  be  flattened  out  and  heated  in  a  platinum  spoon  with 
some  bisulphate  of  potash,  it  will  become  yellow  from  the  silver 
on  the  surface  being  dissolved.     On  re-melting  the  flattened  disc,  a 
silver-white  globule  is  again  obtained. 

23.  Copper  and  Tin  unite  into  a  gray  and  partially  malleable  bead, 
the  surface  of  which,  in  the  0  F,  becomes  more  or  less  thickly  encrusted 
with  cauliflower-like  excrescences  of  oxide. 

24.  Copper  and  Zinc  do  not  unite,  per  se,  into  a  globule,  the  zinc 
burning  into  oxide.     Under  carb.  soda,  or  carb.  soda  and  borax,  brass 
is  readily  formed. 

25.  Copper  and  Lead  form  a  dark  gray  globule,  which  is  sufficiently 
malleable  to  admit  of  being  extended  on  the  anvil. 

26.  Copper  and  Thallium  melt  into  a  dark  gray  malleable  globule. 

27.  Lead  and  Tin  unite  readily,  but  the  globule  commences  imme- 
diately to  oxidize,  throwing  out  excrescences  of  white  and  yellow 
oxide.     On  removal  from  the  flame  it  still  continues  in  ignition,  and 
pushes  out  further  excrescences.     The  unoxidized  internal  portion  (if 
any  remain)  is  malleable. 

28.  Lead  and  Bismuth  unite  readily  :  the  molten  globule  acquires 
a  thin  dark  coating  of  oxide  on  the  surface  only,  and  admits  of  being 
flattened  out,  more  or  less,  upon  the  anvil. 

29.  Lead  and  Thallium  form  a  malleable  globule. 

30.  Bismuth  and  Tin  unite  readily,  but  the  fused  mass  immediately 
throws  out  excrescences,  and  becomes  covered  with  a  dense  crust  of 
oxides.     The  reaction,  however,  is  not  so  striking  as  with  lead  and  tin. 

31.  Thallium  and  Tin  exhibit  the  same  reaction  as  lead  and  tin. 
but  the  cauliflower-like  excrescences  are  brownish-black.     1876, 


THE 


fumVERSITY 


PAET   II. 


ORIGINAL    TABLES 


(BASED  ESSENTIALLY  ON  BLOWPIPE  CHARACTERS) 


DETERMINATION  OF  ALL  KNOWN  MINERALS. 


PAET   II. 


INTRODUCTION 


In  these  Tables  for  the  Determination  of  Minerals,  an  attempt 
has  been  made  to  place  in  the  same  Table,  or  under  its  secondary 
sub-divisions,  those  minerals  only  which  are  related  to  each  other : 
related,  that  is,  not  by  a  single  determinative  character,  but  by  their 
composition  and  characters  generally.  It  is  not,  of  course,  possible 
to  effect  this  with  complete  success  in  all  cases;  but  the  present 
Tables,  it  is  thought,  will  be  found  for  the  greater  part  to  be  at  least 
free  from  the  startlingly  incongruous,  and  hence  objectionable,  group- 
ings seen  in  Determinative  Mineral  Tables  hitherto  published.  At 
the  same  time,  as  regards  ready  application  and  efficacy  in  a  purely 
determinative  point  of  view,  the  present  Tables  will  compare  favour- 
ably, it  is  hoped,  with  other  efforts  in  this  direction.  In  using  the 
Tables,  the  student  is  assumed  to  be  familiar  with  the  more  common 
blowpipe-operations  and  reactions,  as  given  in  Part  I  of  this  Essay. 
It  has  not  been  thought  necessary,  therefore,  in  prefixing  to  subordi- 
nate sections  the  headings  "  Cu  reaction,"  "  Pb  reaction,"  "Na  re- 
action," &c.,  to  give  these  reactions  in  full. 

The  present  work  is  not,  of  course,  intended  to  serve  as  a  substi- 
tute for  an  ordinary  text-book,  but  simply  as  an  adjunct  to  the  latter. 
To  add,  however,  to  its  usefulness,  the  leading  characters  of  each 
species,  including  Composition,  System  of  Crystallization  (with  an 
occasional  angle),  Hardness,  Specific  Gravity,  Colour,  &c.,  are  briefly 
given.  The  composition  is  stated  in  percentage  values  in  most  cases ; 


96  BLOWPIPE   PRACTICE. 

but  in  others  merely  the  components,  as  separated  by  analysis— e.  g., 
CaO,  FeO,  A1203,  Fe2O3,  CO2,  SiO3,  &c.— are  stated.  The  student 
will  thus  be  able,  after  determining  a  mineral  by  the  Tables,  to 
verify  its  composition  as  a  confirmatory  test. 

Tne  names  of  the  Crystal  Systems  are  printed  chiefly  in  abbrevi- 
ated form,  as  follows  : — Reg.  (  —  Regular,  Tesseral,  Isometric,  Mono- 
metric,  &c.);  Tet.  (  =  Tetragonal,  Quadratic,  Dimetric,  &c.)  ;  Hex. 
(  =  Hexagonal),  or  Hemi-Hex.  (  —  Khombohedral  and  other  Hemi- 
Hexagonal  forms) ;  JKh.  (  =  Rhombic,  Ortho-Rhombic,  Trimetric,  &c.) ; 
Clino-Rh.  (=  Clino-Rhombic,  Monoclinic,  Oblique  Rhombic,  &c.)  ; 
Anorth.  (  =Anorthic,  Triclinic,  Clino-rhomboidal,  &c.)  In  Rhombic 
and  Clino-Rhombic  crystals,  the  prism  angle  ( =  oo  P :  oo  P.  Nau- 
mann)  is  sometimes  given  under  the  symbol  of  V :  V,  and  other 
interfacial  angles  are  occasionally  stated.* 

Hardness  ( =  H)  refers,  of  course,  to  the  universally  adopted  Scale 
of  Mohs.  This  scale  is  given  below,  together  with  a  roughly  corres- 
ponding scale  (published  by  the  author  in  1843)  to  serve  as  a  substi- 

*  In  the  system  of  crystallographic  notation  long  followed  by  the  author-  one  that  possesses 
the  advantage  of  allowing  the  symbols  to  be  readily  translated  into  words — all  forms  (apart 
from  those  of  the  Regular  System,  and  certain  special  forms  of  the  Hexagonal  System,  in  the 
case  of  which  it  is  more  convenient  to  employ  arbitrary  symbols)  are  referred  to  one  of  three 
sets,  namely :  Vertical  forms  (parallel  with  the  vertical  axis) ;  the  Basal  form  (parallel  with  the 
basal  or  middle  axes) ;  and  Polar  or  Pyramidal  forms  (inclined  towards  the  vertical  axis  or 
principal  poles  of  the  crystal).  Vertical  forms,  generally,  are  denoted  by  the  common  symbol 
V ;  the  basal  form,  by  B ;  and  polar  or  pyramidal  forms,  by  P.  When  a  form  lies  parallel  to 
any  axis,  the  sign  of  the  axis  (where  this  is  necessary  to  indicate  the  position  of  the  form)  is 
placed  above  the  symbol.  Thus  V  denotes  a  vertical  form  consisting  of  planes  parallel  with  the 
vertical  axis  only,  as  the  upright  planes  of  a  rhombic  prism,  for  example ;  whilst  V  (in  verbal 
language,  a  "  Front  Vertical,"  =  a  Macro-Vertical  or  Ortho- Vertical,  according  to  the  System) 
denotes  a  form  parallel  with  the  right-and-left  transverse  axis  (=  the  macrodiagonal  or  ortho- 
diagonal,  as  the  case  may  be);  and  V  or  V  denotes  a  "Side-Vertical,"  " Brachy- Vertical "  or 
"  Clino-Vertical,"  parallel  with  vertical  and  brachy-axis,  or  vertical  and  clino-axis,  according 
to  the  System.  B,  the  symbol  of  the  basal  form,  needs  no  axial  signs,  as  it  cannot  vary.  The 
polar  forms  comprise :  Polars  or  Pyramids  proper,  Front  Polars,  and  Side  Polars  (or  macro- 

polars,  brachy-polars,  &c.),  and  are  indicated,  respectively,  by  the  symbols  P,  "P,  and  P  or  P 
(with  secondary  signs  where  necessary,  as  in  the  Clino-Rhombic  and  Anorthic  Systems).  Values 
placed  before  a  symbol,  as  2P,  $P,  &c.,  refer  to  the  vertical  axis ;  those  placed  after  a  symbol, 
as  V2  or  V2,  refer  to  one  of  the  middle  axes,  either  understood  conventionally,  or  indicated  by 
its  sign  above  the  figure.  It  is  of  course  evident  that  110  other  forms  than  Vertical,  Basal,  or 
Polar  forms  can  possibly  be  present  in  any  crystal  Hence,  by  the  employment  of  the  sym- 
bols V,  B,  and  P,  with  modifications  as  described  above,  the  position  of  a  given  form  becomes 
taken  up  by  the  eye  at  a  glance,  and  without  risk  of  misconception. 


INTRODUCTION    TO    MINERAL    TABLES. 


97 


tube  where  the  minerals  o:  which  the  scale  of  Mohs  consists  may 
not  be  at  hand. 


SCALE  OF  MOHS. 

CHAPMAN'S  CONVENIENT  SCALK,  TO  CORRESPOND 

WITH  THAT   OF  MoHS. 

1       .  Talc. 

I 

.  .  Yields  to  the  finger-nail. 

2       .  Rock  Salt. 

2 

.  .  Doss  not  yield  to  the  nail,  but  is  scratched 

3      .  Calcite. 

by  a  copper  coin. 

4       .  Fluor  Spar. 

3 

.  .  Scratches  a  copper  coin  (i.  e.,  a  copper 

5       .  Apatite. 

coin  proper,  not  a  modern  bronze  coin), 

(>       .  Orthoclase. 

but  is  also  scratched  by  one. 

7       .  Rock  Crystal  (Quartz). 

4 

.  .  Not   scratched   by   a   copper    coin,    but 

8       .  Topaz. 

easily  scratched  by  a  penknife.     Does 

9       .  C  >ruirlum. 

not  scratch  ordinary  window-glass. 

10      .  Diamond. 

5 

.  .  Scratches  glass  very  feebly,  leaving  its 

powder  on  it. 

6 

.  .  Scratches  glass  strongly.     Not  scratched 

by  a  penknife,  but  yields  to  a  hard  file. 

Readily  scratched  by  a  piece  of  quartz. 

t 

7 

.  .  Scarcely  touched  by  a  file. 

8 

-  9  -  10  .  .  Harder  than  quartz. 

Convenient  objects  for  the  comparison  of 
minerals  possessing  a  higher  degree  of  hard- 
ness than  No.  7,  cannot  readily  be  found  ;  but 
these  minerals  are  few  in  number,  and,  as  a 
rule,  they  are  easily  distinguished  by  other 
characters. 


The  sign  G  indicates  specific  gravity.  This  character  is  ascertained 
very  expeditiously  by  the  spring  balance  contrived  by  Professor  Jolly 
of  Munich ;  but  where  an  instrument  of  this  kind  is  not  at  hand,  a 
small  pair  of  ordinary  scales  may  be  conveniently  used.  The  centre 
of  one  pan  is  perforated  for  the  passage  of  a  horse-hair  with  running 
noose  (to  hold  the  mineral),  or  is  provided  on  its  under-side  with  a 
small  hook  to  which  the  hair  is  attached,  and  the  strings  of  this  pan 
should  be  somewhat  shortened.  The  mineral — a  small  crystal  or 
fragment  of  about  a  gramme  or  couple  of  grammes  in  weight — is 
weighed  first  in  the  ordinary  way,  and  the  weight  is  then  taken 
whilst  the  mineral  is  suspended  in  distilled  water.  If  $  equal,  the 

the  weight  in  air,  and  w  the  weight  in  water,  G  = .     Bodies 

a  -  w 

which  are  soluble  in  water  may  be  weighed  in  alcohol  or  other  suit- 
able liquid  of  known  sp.  gr.     Galling  this  latter,  $?',.  and  the  weight 

of  the  mineral  in  the  liquid.  W'  the  true  sp.  «i?.  becomes ,  G', 

a-  w 


98  BLOWPIPE    PRACTICE. 

In  other  words,  the  sp.  gr.  of  the  substance  as  found  by  the  liquid, 
must  be  multiplied  by  the  sp.  gr.  of  the  latter. 

In  testing  the  solubility,  &c.,  of  minerals  in  acids,  a  small  frag- 
ment of  the  substance  should  be  reduced  to  powder;  and  some  of  the 
latter  (inserted  into  a  test-tube  by  a  narrow  strip  of  glazed  paper 
folded  gutter-wise)  may  be  covered  to  the  depth  of  about  half-an-inch 
with  the  acid  to  be  employed.  The  tube  may  then  be  warmed,  so  as 
to  bring  the  acid  gently  to  the  boiling-point,  over  the  flame  of  a 
small  spirit  lamp  or  Bunsen  burner.  Or,  in  place  of  the  test-tube,  a 
small  porcelain  capsule,  provided  with  a  short  handle,  may  be  used. 

In  the  examination  of  minerals  for  the  presence  of  earths  and 
alkalies,  a  small  direct-vision  spectroscope  will  be  found  very  service- 
able. The  small  pocket  spectroscopes,  3J  inches  long,  with  attached 
scale,  made  by  Browning  of  London,  cannot  be  too  highly  recom- 
mended. Many  minerals  (Calcite,  Gypsum,  Polyhallite,  Strontianite, 
Celestine,  Barytine,  Lepidolite,  &c.,  &c.)  give  characteristic  spectra  by 
sufficiently  prolonged  ignition  in  the  outer  border  of  a  Bunsen  flame, 
but  the  reaction  becomes  in  most  cases  greatly  intensified  by  moisten- 
ing the  ignited  substance  with  hydrochloric  acid,  as  described  at 
page  55  and  in  many  of  the  following  Tables.  In  the  Tables  proper, 
all,  or  practically  all,  known  species  are  inserted ;  but  each  Table  is 
followed  by  an  Explanatory  Note,  in  which  the  commonly  occurring 
or  important  species  of  the  Table  are  alone  referred  to.  In  these 
notes,  crystallographic  and  other  distinctive  characters  are  given  in 
somewhat  greater  detail. 


INDEX  TO   THE  TABLES. 


A.-THE  MINERAL  PRESENTS  A  METALLIC  LUSTRE. 

A1. — A  small  fragment  ignited,  BB,  on  charcoal  volatilizes  wholly  or  partly. 

(1)  It  gives  As  fumes,  but  no  sulphur-reaction  with  carb.  soda TABLE  I. 

(2)  It  gives  As  fumes  and  sulphur-reaction TABLE  II. 

(3)  It  gives  reaction  of  Sulphur  or  Selenium,  but  no  fumes  of  Sb  or  Te. 

TABLE  III. 

(4)  It  gives  sulphur- reaction,  and  fumes  of  Sb  or  Te TABLE  IV. 

(5)  It  gives  fumes  of  Sb  or  Te,  but  no  sulphur-reaction TABLE  V. 

(6)  It  gives  no  reaction  of  S,  Se,  Te,  Sb,  or  As TABLE  VI. 

A2. — A  small  fragment  ignited  on  charcoal  does  not  perceptibly  volatilize. 

(1)  It  fuses,  BB,  on  charcoal  into  a  globule ,  . .  TABLE  VII. 

(2)  It  is  infusible,  or  fuses  only  on  the  thin  edges TABLE  VIII. 

B.— THE  MINERAL  PRESENTS  A  SUB  METALLIC  ASPECT. 

(1)  It  is  easily  fusible  or  reducible  per  se TABLE  IX. 

(2)  It  is  infusible,  or  fusible  only  on  thin  edges TABLE  X. 

C.-THE  MINERAL  PRESENTS  A  VITREOUS,  PEARLY,  EARTHY, 
OR  OTHER  NON  METALLIC  ASPECT. 

C1.—  A  small  fragment  takes  fire  when  held  against  a  candle  or  Bunsen-flame. 

(1)  It  burns  with  blue  flame  and  sulphurous  or  alliacceous  odour. .  TABLE  XI. 

(2)  It  burns  with  bituminous  or  aromatic  odour TABLE  XH. 

C2. — The  mineral  is  not  inflammable.     It  is  readily  dissolved  or  attacked 
by  fusion  with  borax  or  phosphor-salt. 

(1 )  It  is  attacked  with  effervescence  by  dilute  hydrochloric  acid,  TABLE  XIII . 

(2)  It  emits  As  fumes  by  fusion  with  carb.  soda  on  charcoal TABLE  XIV. 

(3)  It  emits  Sb  fumes  by  fusion  with  carb.  soda  on  charcoal TABLE  XV. 

(4)  It  gives  sulphur-reaction  with  carb.  Jjda TABLE  XVI, 


ICO  INDEX    TO   THE    TABLES. 

(5)  Its  solution  in  nitric  acid*  gives  a  canary-yellow  pre.  with  molyb- 

date  of  ammonia TABLE  XVII 

(6)  Its  powder,  moistened  with  sulphuric  acid  and  alcohol,  communi- 

cates a  green  colour  to  the  flame  of  the  latter TABLE  XVIII. 

(7)  It  gives  chlorine  (I  or  Br)  reaction  (azure  or  green  flame)  by  fusion 

with  phosphor-salt  and  copper  oxide TABLE  XIX, 

(8)  It  evolves  orange-red  fumes  when  warmed  with  a  few  drops  of 

sulphuric  acid  in  a  test-tube TABLE  XX, 

(9)  It  corrodes  the  glass  when  warmed  in  powder  with  sulphuric  acid 

in  a  test-tube TABLE  XXI. 

(10)  It  forms  by  fusion  with  carb.  soda  and  nitre  an  alkaline  mass 

partly  soluble  in  water,  the  solution  assuming  a  blue,  brown, 
or  green  colour  when  boiled  with  addition  of  hydrochloric 
acid  and  a  piece  of  tin  or  zinc TABLE  XXII. 

(11)  It  does  not  produce  any  of  the  above  reactions TABLE  XXIII, 

C3. — The  mineral  is  very  slowly  dissolved,  or  is  only  partially  attacked,  BB,  by 
borax  or  phosphor-salt. 

t  It  is  infusible,  or  fusible  only  on  the  thinnest  edges : 

(1)  It  is  hard  enough  to  scratch  ordinary  glass  distinctly,  TABLE  XXIV. 

(2)  It  is  not  hard  enough  te  scratch  glass  distinctly ....  TABLE  XXV . 
ft  It  is  more  or  less  readily  fusible : 

(1)  It  yields  no  water  (or  merely  traces)  by  ignition  in  bulb- 

tube  TABLE  XXVI. 

(2)  It  gives  off  a  distinct  amount  of  water  by  ignition  in  bulb- 

tube TABLE  XXVII. 

NOTE. — In  order  to  appreciate  the  distinctive  character  of  the  respective  sections  C2  and  C3, 
the  student  is  recommended  to  add  a  small  fragment  of  calcite,  gypsum,  fluor  spar,  barytine, 
or  apatite,  on  the  one  hand, — and  a  small  particle  of  orthoclase,  pyroxene,  amphibole,  garnet, 
talc,  quartz,  or  corundum,  on  the  other — to  a  previously  fused  bead  of  phosphor-salt ;  and  to 
observe  the  rapidity  with  which  the  first-named  minerals  are  dissolved  under  the  action  of  the 
blowpipe,  whilst  the  minerals  of  the  latter  group  remain  practically  unaffected,  or  are  very 
slowly  or  incompletely  attacked. 

*  Crush  a  small  fragment  of  the  substance  to  powder.  Place  this,  by  a  bent  slip  of  paper, 
in  a  test-tube.  Drop  a  little  nitric  acid  upon  it,  and  warm  or  boil.  Then  add  some  distilled 
water  and  a  grain  or  two  of  the  molybdate,  and  warm  again. 


TABLES 

FOE  THE  DETERMINATION  OF  MINERALS. 


TABLE    I. 

[Metallic  aspect.     Wholly  or  partly  vol.  with  As  fumes,  but  yielding  no 

S  reaction.] 

A.— Entirely  vol.    (or  leaving  merely  a  feeble   residuum). 

NATIVE  ARSENIC:  Hemi-Hex. ;  H  3-5 ;  G  6-0 ;  tin-white  with  dark 
tarnish. 

Allemontite :  differs  merely  by  having  part  of  the  As  replaced 
bySb. 

NATIVE  BISMUTH — ARSENIC-HOLDING  VARIETIES.  G  97,  BB,  a 
yellow  deposit  on  charcoal.  See  TABLE  VI. 

B.— Partially  vol.,  leaving  distinct  residuum. 

Bi.—  RESIDUUM  MAGNETIC. 

SMALTINE:  (CoNiFe)  28,  As  72.  Keg.;  H  5-5-6;  G  6-5;  greyish 
tin-white.  Chloanthite  (Chathamite)  is  a  highly  nickeliferous  smal- 
tine.  Skutterudite  is  probably  a  mixture  of  smaltine  and  arsenic 
(  =  CoAs2  -f  As). 

LOLLINGITE  :  Fe  27-2,  As  72-8.  Rh. ;  H  5-5-5  ;  G  7-7-4 ;  greyish 
silver-white.  Leucopyrite  (Fe  32-2,  As  66-8  (?) )  is  closely  related. 
In  both,  a  little  S  is  often  present.  (See  below). 

B2.— RESIDUUM  NOT  MAGNETIC. 

(Ni  reaction). 

RAMMELSBERGITE  :  Ni  (CoFe)  28,  As  72.  Rh. ;  H  5-5  ;  G  7-1  ; 
greyish  silver- white. 

NICKELINE:  Ni  (Fe,&c.)  43-6,  As56-4.  Hex.;  H  5-5;  G>5-7'7; 
pale  copper-red. 

(Cu  reaction). 

DOMEYKITE:  Cu  71-7,  As  28-3  ;  H  3-3-5  ;  G  7-7-5  ;  silver-white 
or  tin-white,  tarnished.  ALGODONITE  (Cu  83*5,  As  16-5)  and  WHIT- 
NEYITE  (Cu  88-4,  As  11-6)  are  closely  related,  but  with  higher  sp.  gr. 
(8-8-3). 


•102  BLOWPIPE   PRACTICE. 

(Ag  reaction). 

RITTINGERITE  :  Normally,  AgAs  (?)  with  57'7  Ag,  but  commonly 
contains  sulphur.  Iron-black,  red  by  transmitted  light;  streak 
orange-yellow,  lustre,  mostly,  sub-metallic.  Clino-Rh. ;  H  2-5-3  > 
G  5-63.  (See  TABLE  IX). 


NOTE  ON  TABLE  I. 

The  only  minerals  of  general  occurrence  belonging  to  this  Table  are  Native 
Arsenic,  Smaltine,  and  Nickeline.  N.  Arsenic  is  commonly  in  botryoidal 
masses  with  dark  surface-tarnish,  and  is  readily  distinguished  BB  by  volatilizing 
rapidly  without  fusing.  Smaltine  occurs  most  frequently  in  small  tin-white 
octahedrons  of  sufficient  hardness  to  scratch  glass,  but  is  also  found  in  reticu- 
lated groups  of  minute  indistinct  crystals,  and  massive.  After  roasting,  the 
smallest  particle  imparts  BB  a  rich  blue  colour  to  borax.  Nickeline  is  rarely 
found  otherwise  than  massive.  Its  light  copper-red  or  yellowish-red  colour 
and  high  sp.  gr.  are  its  more  salient  characters.  BB,  it  melts  easily  into  a 
hard  brittle  non-magnetic  globule  with  crystalline  surface.  The  globule 
remains  non-magnetic  after  long  exposure  to  the  flame. 


[103] 


TABLE    II. 

[Metallic  aspect.     As  and  S  reactions.] 
A.— Residuum  magnetic. 

(Co  reaction). 

COBALTIXE  :  Co  (Fe,  &c.)  35-5,  As  45-2,  S  19-3.  Reg.  H  5-5 ;  G 
6 '3;  silver-white,  greyish. 

GLAUCODOT:  (GoFe)  35,  As  45-5,  S  19-5.  Rh. ;  II  5-5,  G  6-2; 
silver-white,  greyish.  Strictly,  a  cobaltic  Mispickel. 

(Ni  reaction). 

GERSDORFFITE  :  Ni  35,  As  45-5,  S  19-5.  Reg. ;  H  5 -5  ;  G  6-6-3  ; 
greyish  tin- white. 

ULLM ANNITE  :  essentially  antimonial :  See  TABLE  IV.  Corynite, 
with  more  As  than  Sb,  is  closely  related.  Also  Wolfachite,  but  the 
latter  is  Rhombic  in  crystallization. 

(Fe  reaction). 

MISPICKEL  or  ARSENICAL  PYRITES  :  Fe  34*4,  As  46,  S  19'6.  Rh. ; 
H  5-5-6;  G  6-0-6-3;  silver- white,  greyish.  GLAUCODOT  and  DANAITE 
are  cobaltiferous  varieties.  ALLOCLASE  is  a  related  steel-grey  species, 
containing  Co,  Ni,  Bi,  &c.  GEIERITE  is  also  a  related  compound, 
but  with  higher  percentage  of  arsenic  (  =  Fe  33'6,  As  60,  S  6*4). 
PLINIAN  is  apparently  a  clino-rhombic  mispickel. 

LOLLINGITE  : — LEUCOPYRITE  :  Normally,  iron  arsenides  free  from 
sulphur,  but  frequently  mixed  with  a  little  FeS2.  See  TABLE  I. 

(Cu  reaction). 

TENNANTITE  (Arsenical .  Tetrahedrite) :  Cu,  Fe,  As,  S,  with  Cu 
averaging  50  p.  c.  Reg.;  H  3-5-4-0  ;  G  4'4-4'5  ;  dark  lead-grey,  iron- 
black.  Some  examples  of  Tetrahedrite,  proper,  contain  traces  of  As. 
See  TABLE  IV. 

B.— Residuum  non- magnetic- 

(Cu  reaction). 

ENARGITE:  Cu  48-5,  As  19,  S  32'5.  Rh. ;  H  3  ;  G  4-44;  dark- 
grey,  iron-black.  -Epigenite  is  closely  related,  but  contains  some 
iron.  Also  Clarite  and  Luzonite. 

COPPER  BINNITE  (  =  Dufrenoysite  of  Damour,  Kengott,  &c.)  Cu 
39,  As  31,  S  30.  R3g. ;  H  25  ;  G  4-6 ;  dark  ste^l-grey,  brownish- 
black;  streak,  red-brown. 


104  BLOWPIPE    PRACTICE. 

(Ag  reaction). 

POLYBASITE  (arsenical  variety,  see  TABLE  IV.)  gives  large  silver- 
globule  by  cupellation.  Iron-black;  red  in  thin  pieces  by  transmitted 
light. 

RITTINGERITE  :  normally,  Ag  As,  but  sulphur  commonly  present. 
Iron-black,  red  by  transmitted  light;  streak  orange-yellow.  See 
TABLES  I.,  IX.,  XIV. 

(Pb  reaction). 

DUFRENOYSITE  (v.  Rath):  Pb  57,  As  21,  S  22.  Rh. ;  H3;  G 
5-5-5-6 ;  dark  lead-grey,  streak  red-brown.  Jordanite  is  nearly 
related.  Pb  51,  As  25,  S  24. 

LEAD-BINNITE  (  =  Binnite  of  Heusser,  Scleroclase  of  V.  Walters- 
hausen,  Sartorite  of  Dana) :  Pb  427,  As  31,  S  26'3.  H  3;  G  54; 
dark  lead-grey,  streak  red-brown. 

GEOCRONITE  (occasional  varieties,  but  the  species  is  essentially  auti- 
monial.  See  TABLE  IV.) 


NOTE  ON  TABLE  II. 

Cobaltine,  Mispickel,  and  Tennantite,  are  the  only  minerals  of  ordinary 
occurrence  belonging  to  this  Table.  Cobaltine  is  commonly  in  small  crystals 
of  a  silver- white  colour  with  slightly  reddish  tinge.  These  crystals  are  most 
commonly  combinations  of  the  cube  and  pentagonal  dodecahedron  °°2,  the 
lafctor  predominating  ;  or  combinations  of  this  pentag.  dodecahedron  with  the 
octahedron.  The  crystals  scratch  glass  easily.  More  rarely,  cobaltine  occurs 
massive,  The  smallest  particle,  after  roasting,  imparts  BB  a  deep-blue  colour 
to  borax, 

Mispickel  or  Arsenical  Pyrites}  occurs  commonly  both  in  masses  and  in 
small  prismatic  crystals  of  the  Rhombic  System,  Its  colour  is  silver-white, 
but  the  surface  soon  assumes  a  greyish  or  other  tarnish.  The  crystals,  which, 
as  a  rule,  scratch  glass  distinctly,  are  mostly  rhombic  prisms  (with  V :  V  — 
111°  12')  terminated  by  two  nearly  flat  and  transversely  striated  planes  (the 

brachydome  or  side-polar  £  P,  with  summit  angle  =  146°  28').  It  fuses  easily, 
with  emission  of  copious  arsenical  fumes,  and  the  fused  globule  (after  sufficient 
exposure  to  the  flame)  attracts  the  magnet  strongly.  Many  varieties  contain 
cobalt,  and  in  some,  nickel  is  present.  Nearly  all  varieties,  moreover,  hold  a 
certain  amount  of  gold  or  silver,  varying  from  a  few  clwts.  to  several  ounces 
per  ton. 

Tennantite  is  readily  distinguished  from  the  above  by  its  dark  colour  and 
low  degree  of  hardness,  as  well  as  by  its  strong  copper-reaction.  It  occurs 
only  in  small  crystals  of  the  Regular  System :  mostly  tetrahedral  combinations, 
or  these  associated  with  the  rhombic  dodecahedron  or  cube. 


[105] 


TABLE    III. 

[S  or  Se  reaction.     No  fumes  of  As,  Sb,  or  Te.] 
A— Fusible:    fusion-product   magnetic. 

(Co  and  Ni  reactions). 

LINN^ITE  (ZiEGENiTE):  (Co,  NiFe)  58,  S  42.  Reg.;  H  5-5;  G  4-9; 
light  steel-grey  with  reddish  tarnish. 

(Ni  reaction). 

MILLERITE:  Ni  35-5,  S  64-5.  Hemi-Hex.,  acicular;  H  3;  G  5-3 
(4*6  Kengott).  Brass  or  bronze-yellow. 

POLYDYMITE:  Ni  59-5,  S  40-5.  Reg.;  H  4-5  ;  G4-81;  lead  grey. 
SAYNITE  is  this  species  mixed  with  copper  pyrites,  galena,  &c.  BEYRI- 
CHITE  is  closely  related. 

(Fe  reaction), 

IRON  PYRITES  (MUNDIC)  :  Fe  46-7,  S  53-3.  Reg. ;  H  6-6-5  ;  G 
4-8-5-2  ;  pale  brass-yellow.  (See  Note,  below). 

MARCASITE  :  Rhombic  in  crystallization ;  otherwise  like  ordinary 
Pyrites. 

PYRRHOTINE  (MAGNETIC  PYRITES):  Fe  60-5,  S  39-5.  Hex.;  H 
3-5-4-5  ;  G  4-4-47;  bronze-yellow;  magnetic.  Horbachite  is  a 
nickeliferous  var. ;  Troilite,  a  meteoric  pyrrhotine. 

(Cu  reaction). 

COPPER  PYRITES  (Chalcopyrite) :  Cu  34-6,  Fe  30-5,  S  34-9.  Tetr. ; 
H  3-5-4;  G  4-1-4-3;  rich  brass-yellow,  often  with  variegated  tarnish; 
streak  greenish-black,  or  dark-green.  HOMICHLINE  is  apparently  a 
mixture  of  this  sp.  and  the  next.  BARNHARDTITE  is  also  closely 
related. 

BORNITE  (Purple  Cop.  Pyrites,  Buntkupfererz) :  consists  of  Cu. 
Fe,  S  in  somewhat  variable  proportions.  The  Cu  averages  50-60 
p.  c.  Many  analyses  shew:  Cu  55  6,  Fe  16-4,  S  28.  Reg.;  H  3; 
G  4-5-5-2;  brownish  copper-red,  rapidly  tarnishing  blue,  green,  &c. ; 
streak  black. 

CUBANITE:  Cu  20,  Fe  41,  S  39  (?).  Reg. ;  H  4;  G  4-1 ;  brass- 
yellow,  streak  black. 

STANNINE  (Tin  Pyrites).  Fusion-globule  in  some  cases  magnetic. 
See  B2. 


106  BLOWPIPE    PRACTICE. 

B  — Fusible :  fusion  product  non-magnetic. 

B». -EVOLVING,  BB,  STRONG  ODOUR  OF  SELENIUM. 

(Cu  reaction). 

BERZELINE  :  Cu  61-6,  Se  38-4.  In  thin  coatings;  very  soft;  silver- 
white,  tarnishing  black. 

CROOKESITE  :  Cu  45-76,  Th  17-25,  Ag  3-71,  Se  33-28.     Compact; 
H  2-5-3  ;  G  6-9 ;  lead-grey.     Colours  flame  intensely  green. 
EUKAIRITE  :  Ag  43-1,  Cu  25-3,  Se  31-6.     Soft,  lead-grey. 
ZORGITE  :    Cu,  Pb,  Se,  in  variable  proportions.      Lead-grey,  soft. 
Comprises,  probably,  several  distinct  species. 

(Pb  or  Bi  reaction). 

CLAUSTHALLITE  :  Pb  72-4,  Se  27'6.  Keg.;  H  2-5-3;  G  8-8-8; 
lead-grey. 

NAUMANNITE:  Ag  (Pb)  73,  Se  27.  Beg.1;  H  2-5 ;  G  8-0;  iron- 
black.  BB,  yields  large  bead  of  silver. 

LEHRBACHITE:  contains  Pb  and  Hg,  with  Se.  H  2-5;  G  7*9; 
lead -grey. 

GUANAJUATITE  :  Bi  69-7,  Se  (S)  30-3.  Apparently  Rhombic,  but 
very  imperfectly  known.  Silaonite  is  a  related  compound.  TETRA- 
DYMITE  :  Essentially  a  bismuth  telluride,  but  sometimes  contains  Se 
and  S.  Refer  to  TABLES  IV.,  V. 

(Hg  reaction). 

TIEMANNITE:  Hg  75,  Se  25.  H  2-5 ;  G  7-7-4;  dark  lead-grey. 
BB,  rapidly  volatilized.  Onofrite  is  an  allied  compound  of  Hg,  Se, 
and  S.  Guadalcazarite,  a  sulphide  of  Hg  and  Zn,  has  part  of  its  S 
replaced  by  Se,  and  should  therefore  be  referred  to  here.  It  is  iron- 
black  in  colour,  with  H  2,  and  G  7-15. 

B2.—NO  SELENIUM  ODOUR  EVOLVED  ON  IGNITION. 
(Cu  reaction). 

CHALKOSINE  (Copper  Glance):  Cu  79-8,  S  20-2.  Rh. ;  H  2-5-3-0; 
G  5-5-5-8.  Dark  metallic-grey,  usually  with  green  or  blue-green 
tarnish. 

STANNINE  (Tin  Pyrites):  Cu,  Sn,  Fe,  &c.,  S.  Reg.;  H  3-5-4; 
G  4-4 ;  yellowish  steel-grey.  Decomposed  by  nitric  acid,  leaving 
residuum  of  SnO2. 

STROMEYERINE:  Ag53,Cu  31-3,  S  15-7.  Rh.;  H  2-5-3-0;  G  6-25. 
Blackish  lead-grey.  BB,  by  cupellation,  gives  large  silver-button. 

\ 


MINERAL    TABLES  I — III.  107 

ZALPAITE:  Ag  71*8,  Cu  14,  S  14-2.  Keg. ;  H  2-2-5;  G  6-9. 
Blackish  lead-grey ;  ductile. 

(Cu  and  Pb  or  Bi  reaction). 

AIKINITE  (Needle  Ore):  Cu  11,  Pb  36,  Bi  36,  S  17.  Rh.;  II  2-5; 
G  67.  Dark-lead  or  steel  grey,  with  yellowish  or  other  tarnish. 
Mostly  acicular  in  quartz. 

WITTICHENITE:  Cu  38-5,  Bi  42,  S  19-5  (1).  Rh.;  H  2-5;  G  4-3-4-6. 
Dark  metallic-grey. 

EMPLECTITE:  Cu  19,  Bi  62,  S  19.  Rh. ;  H  2-2-5;  G  5-2;  tin- 
white,  yellowish.  Acicular  in  quartz. 

CUPRO-PLUMBITE:  Cu  20,  Pb  65,  S  15  (  =  Cu2S  +  2  PbS).  Massive, 
with  cubical  cleavage;  dark  lead  grey.  H  2-5  ;  G  6-4.  ALISONITE 
is  a  related  compound,  but  with  more  copper  (  =  3  Cu2S  -h  PbS). 

(Pb  or  Bi  reaction). 

GALENA  (Lead  Glance) :  Pb  86'6,  S  13-4.  Reg. ;  cleavage  cubical; 
H  2-5;  G  7-3-7-6.  Lead-grey. 

BISMUTHINE  (Bismuth  Glance):  Bi  81-25,  S  18-75.  Rh.;  H  2-2-5; 
G  6-4-6-7.  Light  metallic-grey,  often  iridescent. 

COSALITE  :  Pb  (Ag)  41-7,  Bi  42-2,  S  16*1 ;  Lead-grey;  H  abt.  2-0. 
Retzbanyite,  a  related  compound. 

(Ag  reaction). 

ARGENTITE  (Silver  Glance) :  Ag  87,  S  13.  Reg. ;  H  2  ;  G  7-2-7-4. 
Blackish  lead-grey,  iron-black  ;  malleable.  ACANTHITE  has  the  same 
composition,  but  is  Rhombic  in  crystallization. 

#*#  See,  also,  the  Cu-Ag  sulphides,  Stromeyerine  and  Zalpaite, 
above. 

(Hg  reaction). 

METACINNABARITE  :  Hg  86-2,  S  13-8.  Black,  streak  black.  G  7-7. 
H  1-5-2.  Guadalcazarite  is  identical  or  closely  related. 

C.— Infusible,  or  Fusible  on  edges  only. 

(Mo  reaction.     Flame  tinged  pale-green). 

MOLYBDENITE  :  Mo  59,  S  41.  Hex.  1 ;  H  1-1  -5 ;  G  4-4-4-8.  Light 
lead-grey.  Mostly  in  flexible  plates  and  scaly  masses,  which  mark  on 
paper  and  otherwise  much  resemble  graphite,  but  easily  distinguished 
by  communicating  a  distinct  yellowish -green  colour  to  the  outer 
flame,  as  well  as  by  sulphur  reaction,  and  higher  sp.  gr. 


108  BLOWPIPE    PRACTICED 

(Zn  reaction). 

SPHALERITE  or  ZINC  BLENDE  :  Some  varieties,  only,  are  metallic  or 
sub-metallic  in  lustre.  Streak  pale-brown.  See  TABLES  X.  and  XVI. 

(Mn  reaction), 

ALABANDINE  :  Mil  63-2,  S  36-8.  Black,  brownish,  dark  steel-grey. 
Streak  greenish.  Lustre  sub-metallic.  See  TABLE  X. 

HAUERITE:  Mn  4  6 '2,  S  53-8.  Dark  red-brown,  blackish-brown. 
Streak  brownish.  Lustre  sub-metallic,  only.  See  TABLE  X. 


NOTE  ON  TABLE  III. 

The  minerals  of  comparatively  general  occurrence  belonging  to  this  Table, 
although  more  numerous  than  those  of  Table  II.,  do  not  exceed  ten  or  eleven 
in  number.  They  may  be  arranged,  as  regards  determination,  under  two 
leading  groups,  according  to  colour.  In  the  first  group,  the  colour  is  some 
shade  of  metallic  yellow  or  red  ;  and  in  the  second,  metallic  grey  or  black. 
The  first  group  includes  Iron  Pyrites,  Marcasite,  Pyrrhotine,  Copper  Pyrites, 
and  Bornite.  The  second  group  includes  Argentite,  Molybdenite,  Galena, 
Bismuthine,  and  Chalkosine,  with,  exceptionally,  certain  dark  varieties  of 
Zinc  Blende,  in  which  the  lustre  inclines  to  metallic. 

(Colour  pale  brass-yellow :  H  —  6'0  or  more). 

Iron  Pyrites  and  Marcasite  belong  to  this  section :  they  are  sufficiently  hard 
to  scratch  glass  distinctly.  Iron  Pyrites  occurs  both  massive  and  in  crystals. 
The  latter  are  commonly  cubes  (with  faces  marked  by  alternate  striae),  or 
combinations  of  cube  and  octahedron,  or  combinations  of  the  cube  and  the 
pentagonal  dodecahedron  2Q° ,  or  this  pentag.  dodecahedron  alone.  Marcasite 
presents  the  same  composition  (FeS2),  but  differs  by  its  Khombic  crystallization, 
and  its  greater  tendency  to  fall  into  decomposition.  The  crystals  are  com- 
monly flat  prismatic  combinations,  with  largely  developed  basal  plane,  and 
V :  V  =  106°5' ;  and  they  are  frequently  in  twinned  forms,  or  grouped  in  crested 
rows  ;  whence  the  name  "spear  pyrites,"  "cockscomb  pyrites,"  etc.,  applied 
to  the  species. 

(Colour  brass -y Mow,  bronze-yellow,  or  reddish:  H  under  5*0). 
Pyrrhotine  or  Magnetic  Pyrites,  Copper  Pyrites,  and  Bornite,  belong  to  this 
section ;  none  scratch  glass.  Pyrrhotine  is  bronze-yellow,  almost  always 
massive,  and  more  or  less  magnetic,  sometimes  showing  polarity.  Copper 
Pyrites  is  rich  brass-yellow,  often  with  variegated  tarnish  (  =  "Peacock  Ore," 
etc.),  and  its  streak  is  blackish-green.  It  is  commonly  massive;  but  occurs 
also  in  Tetragonal  crystals,  mostly  small  tetrahedrons  or  sphenoids,  much 
resembling  regular  tetrahedrons.  Bornite  or  Purple  Copper  Pyrites  has  pro- 
perly a  peculiar  reddish  colour  (whence  "horse-flesh  ore"),  but  this  becomes 
rapidly  obscured  by  a  blue  or  green  tarnish.  It  is  nearly  always  massive,  and 
its  streak  is  black  without  any  shade  of  green  in  the  colour. 


MINERAL   TABLES  : — HI.  1  09 

(Colour  metallic  grey  or  black:  flexible  in  thin  pieces,  or  malleable). 
This  section  includes  Argentite  and  Molybdenite.  Argentite  is  at  once  dis- 
tinguished by  its  dark  colour  and  its  malleability  >  as  well  as  by  its  high  sp. 
gr.  (over  7'0),  and  by  yielding,  BB,  a  large  silver-globule.  When  crystallized, 
it  is  mostly  in  combinations  of  cube,  octahedron,  and  rhombic  dodecahedron, 
but  the  crystals  #re  commonly  distorted.  It  occurs  also  frequently  in  leafy 
and  filiform  examples.  Molybdenite  is  light  lead-grey,  mostly  in  scaly  or 
leafy  masses,  very  soft  and  flexible,  but  not  malleable.  It  is  readily  dis- 
tinguished by  the  yellowish-green  colour  which  it  communicates  to  the  outer 
edge  of  the  Bunsen  or  blowpipe  flame,  and  by  its  infusibility.  It  forms,  BB, 
011  charcoal  a  white  deposit  of  MoO3. 

(Colour  metallic  grey  or  black :  BB,  on  charcoal  a  yellow  deposit). 
This  section  includes  Galena  and  Bismuthine,— the  first  of  very  common 
occurrence,  the  latter  comparatively  rare.  Galena  is  distinguished  by  its 
rectangular  or  cubical  cleavage,  and  its  high  sp.  gr.  (  =  7 '3-7 '7).  When 
crystallized,  it  is  commonly  in  cubes  or  in  combinations  of  cube  and  octahedron. 
The  fusion-globule  is  malleable,  and  it  generally  yields  a  little  silver  on  cupel- 
lation.  Bismuthine  is  mostly  in  fibrous  masses  or  acicular  crystals.  It  melts, 
if  held  (in  the  form  of  a  thin  splinter)  against  the  outer  edge  of  the  flame, 
without  the  application  of  the  blowpipe.  Its  nitric-acid  solution  yields  a  white 
precipitate  on  the  addition  of  water. 

(Colour  blackish  metallic-grey.     Surface  usually  encrusted  here  and  there  with  a 

greenish,  earthy  efflorescence. ) 

This  section  (as  regards  minerals  of  common  occurrence)  contains  Chalkosine, 
Cu2S,  only.  Easily  distinguished  by  its  marked  copper-reactions.  Forms 
BB  no  coating  on  charcoal,  but  boils,  spirts,  and  yields  a  copper-globule. 
Commonly  massive.  When  crystallized,  mostly  in  small,  Rhombic  com- 
binations of  pseudo-hexagonal  aspect. 

(Colour  black  or  brownish-black.     Lustre  properly  sub-metallic.     Streak  pale- 
brown.     Infusible,  or  practically  so). 

Certain  dark  varieties  of  Zinc  Blende  (Black  Jack)  may  be  referred  to  here, 
as  these  are  sometimes  mistaken  for  galena.*  Their  infusibility,  brownish 
streak,  and  comparatively  low  sp.  gr.  (  =•  about  4*0),  constitute  their  more 
distinctive  characters.  Mixed,  in  powder,  with  carb.  soda  and  a  little  borax, 
they  yield,  BB,  on  charcoal  a  ZnO  sublimate. 

*  A  practical  illustration  of  this  came  under  the  author's  notice  in  Colorado  a  few  years  ago. 
He  was  asked  to  look  at  a  somewhat  roughly  constructed  reverberatory  that  had  been  recently 
jtut  up  for  the  smelting  of  lead  ore,  but  which  had  turned  out  a  failure.  The  ore,  it  appeared, 
got  into  a  pasty  mass  holding  a  little  reduced  lead,  and  would  not  work.  After  examining  the 
furnace,  and  seeing  nothing  particularly  amiss  in'it,  the  writer  asked  to  look  at  the  ore  This 
was  regarded  at  the  furnace  as  a  tolerably  clean  galena,  but  was  found  to  consist  of  nearly  two- 
thirds  "  Black  Jack  "  mixed  with  galena  in  a  calcareous  gangue.  The  "  pasty  stuff"  which  had 
:-riven  the  furnace  a  bad  name  was  thus  easily  accounted  for.  The  old  name  Blende  (and  the 
newer  Sphalerite)  is  based  on  this  deceptive  aspect.  In  general,  however,  the  lustre  is  non- 
metallic,  or  at  most,  sub-metallic. 


[110] 


TABLE    IV. 

[S  reaction.     Sb  or  Te  fumes.] 
A.— On  charcoal,  BB,  a  white  deposit. 

Al.— ENTIRELY  AND  RAPIDLY  VOL. 

STIBNITE  (Antimony  Glance,  Grey  Antimony  Ore):  S  28-24, 
Sb  7176.  Rh  ;  H  2;  G  4-5-4-7.  Lead-grey,  often  with  iridescent 
or  dark  tarnish.  Melts  per  se  in  outer  edge  of  the  flame  without  the 
aid  of  the  blowpipe.  See  also  the  note  below. 

CINNABAR  (HgS).  Some  dark  or  lead-grey  varieties.  Streak  red; 
G  7 '7-9.  Inflammable.  Lustre,  as  a  rule,  non-metallic.  (See 
TABLE  XI). 

AS.— PARTIALLY  VOL.,  A  LARGE  SILVER-GLOBULE  REMAINING. 

(The  minerals  of  this  section  present  as  a  rule  a  sub-metallic  aspect.  The 
three  first  are  slightly  translucent  in  thin  pieces,  and  have  a  red  streak). 

MIARGYRITE:  S  21-8,  Sb  41-5,  Ag  36-7.  Clino-Rh. ;  H  2-2-5; 
G  5-18-5-26.  Iron-black,  streak  dull-red. 

PYRARGYRITE  (Dark  Red  Silver  Ore):  S  17-7,  Sb  22-5,  Ag  59-8. 
Hemi  Hex. ;  H  2-2-5  ;  G  5-75-5-85.  Iron-black,  reddish,  streak  red. 

POLYBASITE  :  S,  Sb  (As),  Ag  64-74  p.  c. ;  Cu  sometimes  present. 
Rh. ;  H  2-5  ;  G  6-0-6-2.  Iron-black;  streak,  black,  red.  Polyargy- 
rite  is  closely  related,  but  is  Regular  in  crystallization. 

STEPHANITE  (Melanglanz,  Brittle  Silver  Ore):  S,  Sb  (As),  Ag  (Cu) 
68  p.  c.  H  Rh. ;  H  2-5  ;  G  6-3.  Iron-black,  dark  lead-grey,  often 
iridescent. 

A3.— PARTIALLY  VOL  ,  THE  RESIDUUM  MAGNETIC. 

BERTHIERITE:  Average  comp.  S  30,  Sb  57,  Fe  13.  Rh.  (?); 
H  2-5-3 ;  G  4-4-3.  Dark  steel-grey,  often  with  variegated  tarnish. 

ULLMANNITE  (Antimonial  Nickel  Glance):  S  15,  Sb  57'5,  Ni  27-5. 
Reg. ;  H  5-0-5-25  ;  G  6-2-6-5 ;  lead-grey  or  steel-grey,  with  dark  or 
variegated  tarnish.  Some  examples  are  arsenical. 

A*.— PARTIALLY  VOL.,  THE  RESIDUUM  GIVING  STRONG  COPPER-REACTION. 

TETRAHEDRITE  (Grey  Copper  Ore ;  Fahlerz) :  S,  Sb  (As),  Cu  33-44 
p.  c.,  Ag,  Fe,  <fec.  Reg.  (tetrahedral);  H  3-4;  G  4-8-5-4.  Steel- 
grey,  iron-black. 


MINERAL  TABLES: — iv.  Ill 

CHALKOSTIBITE  (Wolfsbergite) :  S  25-7,  Sb  25-4,  Cu  48-9.  Eh.; 
H  3-5 ;  G  4*7-5 ;  dark  lead-grey,  iron-black,  often  with  variegated 
tarnish. 

B.—On  charcoal,  BB,  a  yellow  (or  white  and  yellow)  deposit. 

B'.— PARTIALLY  VOL  ,  A  GOLD  OR  SILVER  GLOBULE  FINALLY  REMAINING. 
(If  the  blowing  be  stopped  too  soon,  a  rich  gold-lead  or  silver-lead  globule 
will  of  course  result.     This  may  be  freed  from  lead  on  the  cupel). 

FREIESLEBENITE  (Donacargyrite).  S  18-8,  Sb  26*9,  Ag  23-8, 
Pb  30-5.  Clino-Rh.  H  2-2-5  ;  G  6-2-6-5  ;  metallic  grey.  Diapho- 
rite  (v.  Zepharovich)  from  Przibram  is  closely  related,  but  is  Rhombic 
in  crystallization.  G  5 -9. 

BRONGNIARDITE  :  S  19-5,  Sb  29-5,  Ag  26,  Pb  25.  Reg. ;  H  2-5  ; 
G  5  -9-6  -0 ;  dark  metallic-grey. 

NAGYAGITE  (Leafy  Tellurium  Ore,  Blattererz) ;  S,  Te,  Pb,  An, 
Ag,  &c.  An,  commonly,  6-9  p.  c.  Tet.,  but  mostly  in  thin  flexible 
laminae.  H  1-1*5  ;  G  6'8-7'2.  Blackish  lead-grey.  Melts  per  se  in 
edge  of  candle-flame. 

B2.— PARTIALLY  VOL.,  THE  RESIDUUM  GIVING  STRONG  COPPER-REACTION. 

BOURNONITE:  S  19-66,  Sb  24-98,  Pb  42-38,  Cu  12-98.  Rh. ; 
H  2-5-3  ;  G  5-7-5-9.  Dark  steel-grey,  iron-black. 

See  also  Tetrahedrite,  some  examples  of  which  contain  Pb  or  Bi ; 
and  Zinkenite  and  Jamesonite,  which  sometimes  contain  a  small 
percentage  of  copper. 

B3.— PARTIALLY  VOL.,  BUT  GIVING  NO  MARKED  REACTION  OF  Ag,  Au,  or  Cu. 

(Sp.  gr.  under  6'0). 

ZINKENITE:  S  22,  Sb  42,  Pb  36.  Rh.,  acicular;  H  2 -5-3 -5  ; 
G  5-3-5-4.  Steel-grey,  lead-grey,  often  with  variegated  tarnish. 

PLAGIONITE:  S  21,  Sb  37,  Pb  42.  Clino-Rh.;  H  2-5;  G  5'4. 
Dark  lead-grey. 

JAMESONITE:  S19-6;  Sb  29-8,  Pb  50-6.  Rh.  H2-5;  G  5-5-5-62. 
Metallic-grey.  Cleavage  basal,  strongly  marked. 

BOULANGERITE:  S  18,  Sb  23,  Pb  59.  Crystn.?;  H  2-5-3 ;  G  5-7-5 -95. 
Dark  lead-grey. 

(Sp.  gr.  over  6'0). 

MENEGHINITE:  S  17-3,  Sb  18-8,  Pb  63'9.  Clino-Rh.,  acicular. 
H  2-5-3;  G  6-34-6*4.  Lead-grey.  Some  examples  appear  to  be 
Rhombic  in  crystallization, 


112  BLOWPIPE    PRACTICE. 

GEOKRONITE  :  S,  Sb,  Pb  65  p.  c.  Some  examples  contain  also  a 
little  Cu.  Rh.  ;  H  2-3 ;  G  6-44-6-54;  lead-grey,  tarnishing  darker. 
Kilbrickenite  is  identical  or  closely  related. 

KOBELLITE  :  S  16-8,  Sb  107,  Pb  54*3,  Bi  18-2.  Crystal.  ?;  H  2-5; 
G  6-15-6-30.  Dark  lead-grey. 

TETRADYMITE  :  Normally,  a  compound  of  Bi  and  Te,  but  frequently 
containing  small  amounts  of  S  or  Se.  Light  steel-grey.  H  1-3  ; 
G  7  "4-7 -9;  flexible  in  thin  pieces.  Wehrlite  is  a  var.  containing  S. 
Some  vars.  also  contain  a  small  percentage  of  Ag.  See  TABLE  V. 


NOTE  ON  TABLE  IV. 

The  only  minerals  of  common  or  general  occurrence  belonging  to  this  Table, 
comprise:  Stibnite,  Tetrahedrite,  Pyrargyrite,  Bournonite,  Zinkemte,  and 
Jamesonite. 

Stibnite  or  Antimony  Glance  (also  known  as  Grey  Antimony  Ore)  is  dis- 
tinguished (if  pure :  id  est,  if  unmixed  with  lead  sulphide,  &c. )  by  its  rapid 
volatilization  before  the  blowpipe  ;  and  by  its  powder  becoming  orange-yellow 
in  a  hot  solution  of  caustic  potash.  It  is  generally  in  masses  of  a  more  or  less 
fibrous  structure  and  light  lead-grey  colour,  or  in  small  Rhombic  prisms  (with 
V  :  V  —  90°54')  terminated  by  the  planes  of  a  rhombic  octahedron.  The  prism- 
planes  are  longitudinally  striated,  but  the  crystals  are  usually  acicular  or  more 
or  less  indistinct.  The  only  species  which  somewhat  resemble  it  are  the  sul- 
phantimonites  Zinkemte,  Jamesonite,  Bournonite,  &c.,  but  these  give  a  lead 
sublimate  on  charcoal,  and  Boumn'-1  gives  also  a  strong  copper-reaction. 
They  are  attacked  but  not  rendered  y.Jow  by  caustic  potash,  but  an  orange 
precipitate  is  thrown  down  if  the  potash  solution  be  neutralized  by  hydro- 
chloric acid.  Jamesonite  is  chiefly  distinguished  by  its  ready  cleavage  in  one 
direction  ;  and  Bournonite  by  its  copper-reaction.  The  latter  mineral  is  often 
found  in  small,  flat,  Rhombic  crystals  with  largely  developed  basal  plane,  and 
V  :  V  =  93°40'.  These  crystals  are  frequently  in  cruciform  or  other  twins.  . 

Tetrahedrite  is  dark-grey  or  iron-black  in  colour,  and  when  crystallized  is 
in  small  tetrahedrons  or  tetrahedral  combinations.  It  gives  strong  copper- 
reactions,  and  some  examples  (Rionite)  contain  zinc ;  others,  silver,  mercury,  &c. 

Pyrargyrite  or  Dark  Red  Silver  ore  is  iron-black  or  reddish  lead-grey  in 
colour,  except  in  thin  pieces  by  transmitted  light,  when  the  colour  appears 
blood- red.  The  streak  is  red  ;  and  the  crystals  are  mostly  combinations  of  the 
hexagonal  prism  with  the  planes  of  one  or  two  rhombohedrons  (R :  R  —  108°42' ; 
\  R  :  \  R  =  137°  58'),  but  the  mineral  is  most  commonly  massive  or  in  indis- 
tinct crystal  aggregations.  It  melts  per  se  in  the  outer  edge  of  the  flame  with- 
out the  aid  of  the  blowpipe.  On  charcoal,  BB,  a  silver  globule  is  easily 
obtained.  Like  other  sulphantimonites,  it  is  attacked  by  hot  caustic  potash, 
and  hydrochloric  acid  precipitates  orange-red  Sb2S3  from  the  solution. 


[113] 


TABLE    V. 

[Metallic  Aspect.     Sb  or  Te  fumes,  but  no  S  reaction.] 

A.— Entirely  volatilizable,  or  leaving  merely  a  minute 
globule  of  metal. 

Ai.— ON  CHARCOAL,  BB,  A  WHITE  DEPOSIT. 

NATIVE  ANTIMONY:  Hemi-Hex.,  cleavable ;  H  3-3-5  ;  G  6*7 ;  tin- 
white.  Converted  by  nitric  acid  into  yellowish- white  powder  (Sb2O3  + 
Sb*O*). 

NATIVE  TELLURIUM:  Hemi-Hex.,  cleavable;  H  2-2-5  ;  G  6-1-6-3; 
tin-white.  Soluble  in  nitric  acid.  Warmed  with  strong  sulphuric 
acid  (the  acid  being  used  in  excess)  forms  a  purplish-red  solution, 
which  becomes  colourless  on  addition  of  water — metallic  Te  falling 
as  a  dark-grey  precipitate.  Forms  also  a  red  solution  when  boiled  in 
powder  with  caustic  potash. 

A*.—  ON  CHARCOAL,  BB,  A  YELLOW  (OK  WHITE  AND  YELLOW)  DEPOSIT. 

TETRADYMITE  :  Bi  52,  Te  48,  but  S  and  Se  often  present  in  small 
proportions.  Hemi-Hex.;  H  1-5-2;  G  7 '4-7 '9;  pale  metallic-grey; 
flexible  in  thin  pieces. 

ALTAITE:  Pb  61-2,  Te  38*8.  Reg.;  H  2-5-3-5;  G  8  1-8-2;  tin- 
white,  yellowish. 

B  —Partially  volatilizable. 

B».— YIELDING,  BB,  OX  CHARCOAL  A  LARGE  GLOBULE  OP  Ag  OR  Au. 

DYSCRASITE  :  Ag  and  Sb  in  several  proportions :  Ag  64-84,  Sb 
15-8-36.  Rh. ;  H  3*5  ;  G  9-4-10.  Silver-white  or  tin- white,  with 
dark  or  yellowish  tarnish. 

HESSITE:  Ag  62-8,  Te  37-2.  Rh. ;  H  2-3*0;  G  8-1-8*5.  Dark 
metallic-grey.  Petzite  is  a  closely  related  mineral,  but  with  a  large 
part  of  the  Ag  replaced  by  Au  (G  8 '7-9 -4). 

SYLVANITE  (Graphic  Tellurium):  Ag,  Au,  Te,  in  variable  propor- 
tions. Sb  and  Pb  also  present  in  some  examples,  Au  25-45,  Ag  l-lo, 
Te  45-56.  Glino-Rh.  (or  Rh.  ? );  H  1-5-2;  G  8-8*4.  Light  steel- 
grey  inclining  to  silver-white  or  pale  yellowish.  Calaverite  is  a 
yellow  var.,  with  Au  44-5,  Te  55-5.  Miillerine  is  also  an  auriferous 
var,,  containing  Pb  and  Sb  in  addition  to  the  normal  components. 


114  BLOWPIPE    PRACTICE. 

B«. -YIELDING,  BB,  A  MAGNETIC  (NICKELIFEROUS)  GLOBULE. 

BREITHAUPTITE  (Antimonial  Nickel  Ore):  Ni  32'2,  Sb  67'8.  Hex. ; 
H  5  ;  G  7 '5-7 '6  ;  pale  copper-red,  mostly  with  bluish  tarnish.  Com- 
monly massive,  or  in  small  tabular  crystals  with  striated  base. 
Isomorphous  with  Nickeline,  TABLE  I.  Part  of  the  Ni  usually 
replaced  by  Fe. 

MELONITE  :  Ni  23-5,  Te  76'5.     Hex.  ?     Pale  reddish-white. 


NOTE  ON  TABLE  V. 

All  the  minerals  of  this  Table  are  of  exceptional  or  merely  local  occurrence. 
Those  which  contain  gold  or  silver  are  easily  recognized  by  the  metallic 
globule  which  they  yield,  BB,  on  charcoal.  The  presence  of  antimony  is 
revealed  by  the  copious  fumes  emitted,  BB ;  and  by  the  formation  of  a 
yellowish-white  powder  (SbW  or  Sb205,  or  a  mixture  of  the  two)  in  nitric  acid. 
The  presence  of  tellurium,  revealed  by  its  blowpipe  reactions,  is  readily  con- 
firmed by  warming  a  small  portion  of  the  substance  in  a  test-tube  about  half 
filled  with  strong  sulphuric  acid,  when  a  reddish  solution  will  result.  On 
addition  of  water,  a  dark  precipitate  of  metallic  tellurium  is  thrown  down. 


[115] 


TABLE    VI. 

[Aspect  metallic.     No  S  reaction.     No  fumes  of  As,  Sb,  or  Te.] 

A     On   charcoal,  BB,  no   sublimate.    (In  closed  tube,  Hg 

Reaction). 

A*.— ENTIRELY  VOL. 

NATIVE  MERCURY.  In  small  fluid  globules  of  a  tin- white  colour. 
G  13-6. 

A«. -PARTI  ALLY  VOL.,  A  SILVER-GLOBULE  REMAINING. 

AMALGAM  :  Properly  an  isomorphous  union  of  Ag  and  Hg  :  hence 
these  components  are  present  in  variable  proportions.  Keg. ;  H  2-3'5  ; 
G  10*8-1 4*10;  brittle.  Arquerite  is  a  variety  containing  86  J  p.  c. 
silver.  Kongsbergite,  a  var.  containing  95  p.  c.  silver.  Some 
amalgams  contain  gold  :  in  these  the  sp.  gr.  is  usually  1 5  or  more. 

B.— On  charcoal,  BB,  a  yellow-sublimate. 

Bi.— MALLEABLE. 

NATIVE  LEAD:  Reg.;  H  1-5;  G  11  -3-1 1-4;  lead-grey;  ductile. 

B2— CLEAVABLE  (OR  NOT  MALLEABLE). 

NATIVE  BISMUTH:  Hemi-Hex.  H  2-5 ;  G  9-6-9-8.  Reddish 
Silver- white,  mostly  with  yellowish  or  variegated  tarnish. 


NOTE  ON  TABLE  VI. 

Native  Bismuth  and  Native  Amalgam  are  the  only  minerals  of  ordinary 
occurrence  belonging  to  this  Table.  N.  Bismuth  is  readily  distinguished  by 
its  ( practical \y)  complete  volatilization  before  the  blowpipe,  with  formation  of 
a  yellow  deposit  of  oxide  on  charcoal.  It  dissolves  rapidly  in  nitric  acid,  the 
solution  yielding  a  white  precipitate  on  the  addition  of  water.  Some  varieties 
contain  traces  of  As,  S,  Te,  &c.  It  occurs  commonly  in  small  cleavable 
masses,  but  occasionally  in  dendritic  and  other  examples.  When  crystallized, 
it  is  mostly  in  small  rhombohedrons  with  basal  plane,  the  principal  cleavage 
being  parallel  with  the  latter.  Amalgam  is  often  in  small  crystals  of  the 
Regular  System,  commonly  in  dodecahedrons  or  combinations  of  cube  and 
octahedron.  In  ordinary  varieties  the  sp.  gr.  exceeds  13 '5.  This  latter 
character,  together  with  the  large  bead  of  silver  which  it  yields,  BB,  and  its 
mercurial  reaction,  serve  sufficiently  to  distinguish  it* 


[116] 

TABLE*  VII. 

[Lustre  metallic.  Not  perceptibly  vol.  Fusible  on  charcoal  into  a  globule,] 
A— Malleable. 

NATIVE  GOLD:  Reg.;  H  2-3;  G  15-5-19-4.  Gold-yellow,  Not 
attacked  by  nitric  acid,  nor  by  blowpipe  fluxes.  Always  contains  a 
small  amount  of  Ag. 

NATIVE  SILVER:  Reg.;  H  2-3;  G  10'5  (or  10-11).  Silver-white, 
often  with  black  surface-tarnish.  Easily  dissolved  by  dilute  nitric 
acid  on  heating  :  a  white  curdy  pre.  (turning  dark-grey  on  exposure) 
is  formed  by  hydrochloric  acid,  or  any  soluble  chloride,  in  the  solution. 

NATIVE  COPPER:  Reg.;  H  2-5-3;  G  8-5-8-9.  Copper-red,  often 
with  dull-brown  tarnish.  Easily  sol.  in  nitric  acid,  forming  a  green 
solution,  which  becomes  deep-blue  on  addition  of  ammonia.  The 
fused  bead  blackens  in  the  OF,  its  surface  becoming  encrusted  with 
CuO.  This  tinges  the  flame  green. 

B  —  Not  malleable. 

(Cu  reaction). 

CUPRITE  (Red  Copper  Ore).  Colour  and  streak  red.  Lustre 
occasionally  sub-metallic.  (See  TABLE  IX). 

TENORITE  (Black  Oxide  of  Copper):  Cu  79-85,  O  20-15.  Rh.  ?  in 
small,  tabular  crystals,  massive,  &c.;  H  2-3 ;  G  6-9-6-5.  Steel-grey 
to  black.  Melaconite  is  an  earthy  or  scaly  var.,  sometimes  pseu- 

domorphous. 

O  (Mn  and  Fe  reactions.) 

WOLFRAM.  Brown,  black.  Lustre  sub-metallic  only.  H  5-5-5  ; 
G  over  7.  An  iron-manganese  tungstate.  (See  TABLE  IX). 

NOTE  ON  TABLE  VII. 

All  the  minerals  of  this  Table,  Tenorite  excepted,  are  of  tolerably  common 
occurrence.  They  are  readily  distinguished  by  the  characters  given  above,  or 
by  the  following  condensed  scheme  : 

Malleable : 

Colour  yellow— N.  Gold. 

white  — N.  Silver. 
"       red      — N.  Copper. 

Brittle  : 

Streak  red— Cuprite. 
"       black  or  brown  : 

BB,  Cu  reaction  — Tenorite. 
"    Mn  reaction — Wolfram. 

These  ifiree  latter  minerals  belong,  properly,  to  other  Tables.  Exceptional  varieties,  only, 
come  under  notice  here. 


[117] 


TABLE    VIII. 

[Lustre  metallic.     Not  perceptibly  vol.     Infusible';  or  fusible  at  the  extreme 
point  or  edges,  only.] 

A— Not  dissolved,  BB,  by  borax  or  phosphor- salt. 

A1.— VERY  SOFT,  BLACK,  MARKING  OR  SOILING. 

GRAPHITE  (Plumbago).  Normally,  pure  carbon :  usually  slightly 
ferruginous,  &c.  Hex.;  H  1-1-5;  G-  1-9-2-3.  Black,  lustrous, 
greasy-feeling. 

A2.-MORE  OR  LESS  MALLEABLE.     SP.  GR.  OVER  11  (IN  MOST  CASES. 
17  OR  HIGHER). 

NATIVE  PLATINUM:  Keg.;  H  4-5;  G  17-18.  Silver- white,  pale 
steel-grey.  Sol.  in  hot  nitro-hydrochloric  acid.  Many  examples  con- 
tain a  small  percentage  of  Fe,  and  thus  act  slightly  or  strongly  on 
the  magnet.  See  under  B1. 

NATIVE  IRIDIUM  or  PLATINUM-!RIDIUM  :  Ir,  Pt,  Rh,  &c.  Reg. 
H  4'5-7;  G  18-23,  usually  about  22.  Greyish  silver-white;  scarcely 
malleable.  Insol.  in  nitro-hydrochloric  acid. 

'OSMIUM-IRIDIUM  or  NEWJANSKiTE.  IrOs,  mostly  with  the  Ir  in 
excess.  Hex.;  H  6-5-7;  G  19*5;  tin-white.  Emits  disagreeable 
odour  of  osmic  acid  when  fused  with  nitre  in  closed  tube. 

IRIDOSMIUM  or  SYSSERSKITE  :  IrOs,  with  Os  predominating. 
G  21-21-2.  Emits  odour  of  osmic  acid  by  ignition  per  se  on  char- 
coal. Otherwise  like  Osmium-Iridium. 

NATIVE  PALLADIUM.  Reg.  H  4-5-5  ;  G  11-8-12-2.  Light  steel- 
grey  or  greyish  tin-white.  Malleable.  Sol.  in  hot  nitric  acid,  form- 
ing a  reddish  solution. 

B— Dissolved  or  readily  attacked  by  fusion  with  borax  or 
phosphor-salt 

B».  -MAGNETIC  BEFORE  OR  AFTER  IGNITION. 

(Malleable). 

NATIVE  IRON  (Meteoric  Iron):  Fe  combined  in  nearly  all  cases 
with  a  certain  percentage  of  Ni.  Reg. ;  H  4-5-5 ;  t>  7-7-8 ;  steel- 
grey,  iron-black. 

PLATINUM-IRON:  Pt  with  10-20  p.  c.  Fe.  Reg.;  H  6;  G  13-15. 
Dark  steel-grey.  Properly,  a  ferruginous  var.  of  Native  Platinum. 


118  BLOWPIPE    PRACTICE. 

Some  examples  (unless  in  fine  filings)  are  not  readily  attacked  by 
borax.     Some  examples,  also,  are  said  to  be  non-magnetic. 

(Brittle :  i.e.  not  malleable). 

MAGNETITE  (Magnetic  Iron  Ore):  Fe  72-4,  O  27-6  (  =  FeO,  Fe'O), 
Keg. ;  H  5'5-6'5  ;  G  4-9-5-2  ;  iron-black,  streak  black  ;  often  exhibits 
magnetic  polarity.  Magno-ferrite  (better  named  Ferro-magnesite)  is 
a  volcanic  variety  in  which  the  FeO  is  essentially  replaced  by  MgO. 
G  4' 6-4' 7.  Jacobsite  is  another  variety,  containing  both  MgO  and 
MnO.  G  4'75.  Many  examples  of  Magnetite  are  also  titaniferous. 
These  might  fairly  rank  as  a  distinct  species,  having  the  same  relation 
to  Magnetite  proper  that  Ilmenite  bears  to  Haematite. 

FRANKLINITE  :  ZnO,  FeO,  MnO,  Fe2O3,  in  variable  proportions,  but 
yielding  the  general  formula  HO,  R2O3.  Reg. ;  H  6-6-5 ;  G  5-5*1  ; 
iron-black,  streak  dark  reddish-brown.  Usually,  more  or  less  mag- 
netic. BB,  in  powder  with  carb.  soda  and  borax,  gives  coating  of  ZnO 
on  charcoal. 

CHROMITE  ;  normally,  FeO,  32,  Cr203  68.  Reg.;  H  5-5;  G  4'3  4-6. 
Iron-black,  streak  dark-brownish.  Lustre,  in  most  examples,  sub- 
metallic  only. 

HEMATITE  (Specular  Iron  Ore):  Fe  70,  O  30  (  =  Fe203).  Hemi- 
Hex.  ;  H  5'5-6'5  ;*  G  5-0-5-3.  Steel-grey,  often  with  variegated 
tarnish ;  streak  cherry-red.  Sometimes  feebly  magnetic.  Martite 
is  a  var.  in  small  octahedrons  altered  from  Magnetite. 

ILMENITE  or  MENACANNITE  (Titaniferous  Iron  Ore).  Fe?O3,  Ti203  in 
variable  proportions.  Henri-Hex.;  H  5-5-6;  G  4-5-5-3.  Iron-black, 
dark  steel-grey;  streak  black  to  brownish-red.  Dissolved  or  attacked 
in  fine  powder  by  hot  hydrochloric  acid,  the  diluted  solution  by  boiling 
with  tin  becoming  first  colourless  and  then  assuming  an  amethystine 
tint. 

ARKANSITE  (variety  of  BROOKITE).  Black,  sub-metallic  lustre. 
See  TABLE  X. 

( Yield  water  in  bulb-tube). 

TURQITE.  Red,  blackish-red ;  lustre  sub-metallic.  See  TABLES 
X.,  XXIII. 

GOETHITE.  Red,  brown;  lustre  sub-metallic  in  some  examples. 
See  TABLES  X.,  XXIII. 


*  As  regards  ordinary  examples;  but  the  scaly  variety,  ^'though  shewing  metallic  lustre,  soil* 
the  hands. 


MINERAL   TABLES  : — Vfll. 

LIMONITE  (Brown  Iron  Ore).     Brown,  streak  yellowish, 
occasionally  sub-metallic.     See  TABLES  X.,  XXIII. 

B».— NON-MAGNETIC  AFTER  IGNITION.  ^V*J  A 

(Strong  Mn  reaction.*  Anhydrom). 

PYROLUSITE  (Black  Manganese  Ore):  Mn  63'2,  O  36'8.  Eh.; 
H  1-1*5;  G  4'7-4-9 ;  iron-black,  dark  steel-grey,  streak  black;  soils 
and  marks.  Ignited,  and  moistened  with  HC  acid,  shews  Ba-lines 
in  spectroscope. 

POLIANITE  :  Identical  with  Pyrolusite  as  regards  composition  and 
general  crystallization,  but  with  H  =  6-7. 

BRAUNITE — HAUSMANNITE.  Aspect  commonly  sub-metallic.  See 
TABLE  X. 

CREDNERITE.  Gives  copper  reactions.  Aspect  commonly  sub- 
metallic.  See  TABLE  X. 

(Strong  Mn  reaction,  and  yielding  aq  in  bulb-tube). 

MANGANITE:  MnO2  90-9,  H2O  9-10.  Rh. ;  H  3'5-4;  G  4'3-4'5 ; 
dark  steel-grey ;  streak,  brown,  black. 

PSILOMELANE  :  MnO,  BaO,  etc.,  with  about  4  or  5  p.  c.  H2O. 
Amorphons  (reniform,  &c.);  H  5-6;  G  3'7-4'7.  Iron-black,  dark 
steel-grey ;  streak,  brownish.  Some  examples  show  distinct  K-line 
in  spectroscope. t 

(No  marked  Mn  reaction.     No  ebullition  by  fusion  with  borax). 

PITCHBLENDE  —  TANTAUTE  —  COLUMBITE  —  YTTROTANTALITE  — 
SAMARSIUTE — EUXENITE.  Lustre  sub-metallic,  only.  See  TABLE  X. 

MUSCOVITE — PHLOGOPITE  —  and  some  other  MICAS.  Lustre  pearly- 
metallic  (pseudo-metallic);  foliated  or  scaly;  streak  white  or  greyish. 
See  TABLES  XXV.,  XXVI. 


NOTE  ON  TABLE  VIII. 

Minerals  of  ordinary  occurrence  belonging  to  this  Table  comprise — in  addi- 
tion to  Graphite— the  iron  ores,  Magnetite,  Haematite,  and  Ilmenite ;  and  the 


*  Dissolved  also,  BB,  by  borax  with  strong  ebullition,  caused  by  liberation  of  oxygen. 

tThis  is  best  seen  by  igniting  the  test-substance,  and  then  moistening  it  with  hydrochloric 
acid.  Green  B  -lines  first  appear  for  a  moment,  after  which  the  red  K-line  cornea  out  very 
distinctly  and  is  tolerably  permanent.  If  a  piece  of  deep-blue  glass  be  held  between  the 
gpectroscope  and  the  Bunsen-flame,  the  yellow  Na-line,  always  present  with  its  accompanying 
glare,  becomes  entirely  obliterated,  and  the  red  K-line  alone  remains  visible.  By  ignition  and 
treatment  with  HC  acid,  nearly  all  manganese  oxides  of  natural  occurrence  give  a  momentary 
Ba-speetrum, 


120  BLOWPIPE    PRACTICE. 

manganese  ores,  Pyrolusite  and  Manganite.  The  other  minerals,  mentioned 
in  the  Table,  are  either  rarely  met  with,  or  otherwise  they  present  merely  a 
sub-metallic  lustre,  and  therefore  come  properly  under  examination  m  a 
succeeding  Table. 

Graphite  occurs  chiefly  in  foliated  or  sub-granular  masses,  more  rarely  in 
hexagonal  tables.  Its  dark  colour,  flexibility,  greasy  feel,  and  property  of 
marking  and  soiling,  are  among  its  more  salient  characters.  The  only  mineral 
which  might  be  mistaken  for  it,  is  the  sulphide  Molybdenite.  The  latter  is 
much  lighter  in  colour,  and  is  at  once  distinguished  by  the  pale  green  or 
yellowish-green  coloration  which  it  imparts  to  the  outer  edge  of  a  Bunsen  or 
other  flame. 

Magnetite  is  sufficiently  distinguished  by  its  magnetism,  and  by  its  black 
colour  and  streak.  When  crystallized,  it  is  commonly  in  octahedrons,  more 
rarely  in  rhombic  dodecahedrons.  Franklinite  and  Chromite  are  closely 
related  to  it,  but  possess,  as  a  rule,  merely  a  sub-metallic  lustre,  and  their 
streak  is  more  or  less  brown  in  colour.  Chromite,  moreover,  gives  BB  with 
borax  a  chrome-green  glass  ;  Franklinite,  with  carb.  soda,  a  strong  manganese  - 
reaction. 

Haematite  presents  many  varieties,  but  that  which  properly  belongs  to  this 
Table  is  the  variety  known  as  Specular  Iron  Ore.  This  is  commonly  in  dark 
steel-grey,  laminar,  crystalline,  or  scaly  masses,  cherry-red  in  the  streak. 
The  crystals  are  rhombohedral  combinations,  often  with  largely  developed 
basal  plane.  R  :R  =  86°10'  ;"B:  R  =  122°30'.  The  scaly  variety  crumbles 
under  the  fingers  ;  the  massive  and  crystalline  varieties  scratch  glass. 

Ilmenite  is  closely  related  to  Haematite,  and  closely  resembles  the  latter  in 
crystallization  and  general  characters,  but  is  usually  darker  in  colour,  with 
blackish,  or  indistinctly  red,  streak.  It  is  best  distinguished  by  the  amethystine 
colour  produced  in  its  hydrochloric-acid  solution  by  boiling  with  tin.  The 
student  must  remember,  however,  that  many  examples  of  magnetite  and 
haematite  are  titaniferous  to  some  extent,  and  with  these  the  reaction  would 
also  be  obtained. 

Pyrolusite  occurs  commonly  in  iron-black  or  dark  steel-grey  fibrous  masses, 
sufficiently  soft  to  soil  the  hands.  It  produces  chlorine  fumes  when  warmed 
with  hydrochloric-acid,  and  the  smallest  fragment  gives  with  carb.  soda,  BB, 
a  strong  reaction  of  manganese  in  the  form  of  a  turquoise-enamel. 

Manganite  is  also  of  a  dark  steel-grey  or  iron -black  colour.  It  occurs  com- 
monly in  groups  of  prismatic  crystals  or  in  coarsely-fibrous  masses.  The 
crystals  belong  to  the  Rhombic  System,  and  are  frequently  twinned.  V  :.V  = 
99°40'.  Its  acid  and  blowpipe  reactions,  generally,  are  the  same  as  in  Pyro- 
lusite, but  it  differs  from  the  Utter  species  by  yielding  watej:  (9-10  per  cent,) 
in  the  bulb-tube, 


[121] 


TABLE    IX, 

[Lustre  sub-metallic.     Readily  fusible  or  reducible  per  se.} 
A.— Wholly  or  partly  volatilizable  by  ignition  on  charcoal. 

A1.— ENTIRELY  VOL. 

(Hg  reaction}. 

CINNABAR  (HgS).  Some  dark  or  lead-grey  varieties.  Streak  red. 
G  8-9.  Inflammable.  See  TABLE  XI. 

(Sb  fumes  and  coating). 

KERMESITE  (Red  Antimony  Ore) :  Sb2S370,  Sb2O330.  Dark  blueish- 
red,  with  cherry-red  streak.  Rh.  (chiefly  acicular  and  fibrous) ;  H  1-5 ; 
G  4-5.  Melts  in  candle-flame.  See,  also,  TABLES  XI.,  XV. 

A*.— PARTLY  VOL.,  A  LARGE  SILVER-GLOBULE  REMAINING. 

(Sb  fumes  and  coating). 

MIARGYRITE:  Ag  367,  Sb  41-5,  S  21-8.  Clino-Rh.  H  2-2-5; 
G  5-18-5-26.  Iron-black  with  cherry -red  streak. 

PYRARGYRITE  (Dark  Red  Silver  Ore):  Ag  59-8,  Sb  22*5,  S  177. 
Henri-Hex. ;  H  2-2-5  ;  G  5-75-5-85.  Dark  lead-grey,  reddish-black; 
streak  cherry-red.  See  Note,  below. 

(As  fumes). 

PROUSTITE  (Light  Red  Silver  Ore):  Ag  65*46,  As  15-15,  S  19-39. 
Red,  blueish-red ;  streak  bright-red.  Lustre,  properly,  non-metallic. 
See  TABLE  XIV. 

RITTINGERITE  :  Ag  (5 7 '1  p.  c.)  with  As,  or  with  Sb,  S  or  Se  (?) 
Clino-Rh. •  H  2-5-3-0 •  G  5-6'3  ;  iron-black  with  variegated  tarnish  ; 
reddish  or  yellow  by  transmitted  light ;  streak,  orange-yellow. 

POLYBASITE  :  Ag,  Cu,  As,  Sb,  S.  Iron-black ;  red  in  thin  pieces 
by  transmitted  light.  Streak,  red,  black.  See  TABLES  III.,  IV. 

A*.—  PARTLY  VOL.,  A  CUPREOUS  GLOBULE  REMAIN^G. 

COVELLINE  (Indigo  Copper  Ore):  Cu  66*46,  S  33-54.  Hex.  (but 
commonly  massive,  nodular,  &c.);  H  1-5-2  ;  G  4-4*6.  Dark  coppery- 
blue,  blackish-blue,  with  black  streak.  Inflammable. 

CHALKOSINE  (Copper  Glance):  Lustre  sub-metallic  in  occasional 
examples,  only.  Dark  iron-grey,  usually  with  greenish  coating  in 
patches.  G  5*6.  See  TABLE  III. 


122 


BLOWPIPE    PRACTICE. 


A*.— PARTLY  OR  WHOLLY  VOL.,  WITH  PRODUCTION  OF  LEAD  GLOBULE  AND 
LEAD  COATING  ON  CHARCOAL. 

PLATTNERITE:  Pb  86-6,  0  134.  Iron-black;  Hex.  (pseudo- 
morphous  after  Pyromorphite  ? );  H  3-4  ? ;  G  9 -4. 

B-— Non-volatile  on  ignition. 

BI.— REDUCIBLE,  BB,  TO  METALLIC  COPPER. 

CUPRITE  (Hed  Copper  Ore):  Cu  88-8,  O  11-2.  Reg. ;  H  3-5-4; 
G  5 -7-6.  Dark  red,  sometimes  with  blueish  or  lead-grey  tinge. 
Streak,  red.  Surface  often  altered  to  green  carbonate.  Tile-ore  is 
an  impure  var.  mixed  with  Fe2O3,  &c. 

TENORITE  (Black  Copper-oxide).  Cu  79-85,  O  20-15.  Mostly 
massive.  H  2-3 ;  G  5'9-6'5.  Blackish  steel-grey,  iron-black. 

B«.— FUSIBLE  INTO  A  MAGNETIC  BEAD. 

(G  7-7-5.     Readily  dissolved,  BB,  by  Phosphor-salt.      With  carb.  soda, 
strong  Mn  reaction). 

WOLFRAM  :  FeO,  MnO,  WO3,  in  somewhat  variable  proportions : 
the  WO3,  76-76-5  p.  c.  Clino-Rh. ;  H  5-5-5;  G  7-1-7-55.  Dark 
brown,  brownish  black,  with  brownish  streak.  See  Note,  below. 

Samarskite — Scarcely  fusible.     Black.     See  TABLE  X. 

(SiO2  reaction  with  Phosphor-salt.     Gelatinizing  in  hot  hydrochloric  acid). 
ALLANITE — ILVAITE  or  LIEVRITE — FAYALITE  :  Black,  brownish  or 
greenish-black.     Lustre,  properly,  non-metallic.     See  TABLE  XXVI. 


NOTE  ON  TABLE  IX. 

Omitting  the  silicates,  Allanite,  Ilvaite,  &c.,  the  lustre  of  which  is  properly 
non-metallic,  the  commonly  occurring  minerals  of  this  Table  comprise  :  Cinna- 
bar, Kermesite,  Pyrargyrite,  and  Proustite,  all  of  which  give  a  marked  sulphur- 
reaction  with  carb.  soda  on  charcoal ;  the  red,  copper-suboxide  Cuprite  ;  and 
the  tungstate,  Wolfram. 

Cinnabar  presents  a  sub-metallic  lustre  in  occasional  examples  only.  Most 
commonly  it  has  a  red  colour  and  non-metallic  aspect.  Its  ready  inflammability 
and  high  sp.  gr.  (8  -  9)  serve  at  once  to  distinguish  it  from  the  other  red  minerals 
of  the  Table.  It  forms  no  deposit  on  charcoal,  but  yields  readily  a  grey  subli- 
mate of  metallic  mercury  if  strongly  ignited  in  a  closed  tube  with  dry  carb. 
soda,  iron- filings,  or  other  reducing  agents.  See  also,  the  Note  to  TABLE  XL 


MINERAL    TABLES  I IX.  1  23 

Kennesite  resembles  Cinnabar  as  regards  rapid  volatilization,  but  it  forms 
on  charcoal  a  dense  white  coating  of  Sb203  or  Sb205,  and  its  sp.  gr.  does  not 
exceed  4 '6.  It  occurs  commonly  in  tufted  groups  of  acicular  crystals,  or  in 
radiated  fibrous  examples.  In  a  hot  solution  of  caustic  potash  it  is  rapidly 
converted  into  an  orange-red  powder. 

Pyrargyrite  and  Proustite  are  closely  akin  by  crystallization  and  chemical 
formulae  ;  but  Pyrargyrite  is  very  dark  in  colour,  and  it  emits,  BB,  dense 
antimonial  fumes  (commonly  accompanied  by  arsenical  odour) ;  whilst  Proustite 
is  distinctly  red,  with  commonly  an  adamantine  or  non-metallic  lustre  and 
certain  degree  of  translucency,  and  it  is  essentially  a  sulpharsenite.  Both 
occur  commonly  massive,  or  in  small  (usually  indistinct)  crystals  of  the 
Hexagonal  System,  the  more  frequent  forms  comprising  a  combination  of 
hexagonal  prism  and  rhombohedron,  and  scalenohedral  combinations.  Twins 
and  hemimorphous  examples  are  common.  Both  species  fuse  per  se  when  held 
against  the  edge  of  a  candle-flame.  The  powder  becomes  immediately  black 
in  a  hot  solution  of  caustic  potash.  Hydrochloric  acid  precipitates  orange- 
br-wn  Sb2S3,  or  yellow  As'2S5,  from  the  solution.  See,  also,  Notes  to  TABLES 
IVT.  and  XIV. 

Cuprite  is  separated  from  the  preceding  minerals  by  yielding  no  sulphur- 
reaction  before  the  blowpipe.  It  occurs  frequently  in  octahedrons  and  rhombic 
dodecahedrons,  with  green  coating  of  malachite  covering  the  entire  surface  of 
the  planes  ;  more  rarely  in  acicular  shapes  arising  from  elongated  cubes.  It  is 
also  frequently  in  massive  examples.  It  dissolves  in  nitric  acid  with  strong 
effervescence  and  production  of  orange-red  nitrous  fumes,  the  Cu*0  being  con- 
verted into  CuO  at  the  expense  of  some  of  the  oxygen  of  the  acid.  The 
solution  is  of  course  green  or  blue  in  colour,  and  becomes  intensely  blue  on 
sufficient  addition  of  ammonia. 

Wolfram  is  readily  distinguished  by  its  dark-brown  or  black  colour,  and 
high  sp.  gr.  (over  7).  It  occurs  massive,  and  very  frequently  in  somewhat 
large  crystals  of  the  Clino-Rhombic  System :  mostly,  flattened  six-planed 
prisms  (composed  of  the  forms  V  and  V)  terminated  by  a  sharply  sloping  base 
and  several  polar  planes.  V  :  V  =  100°37' ;  V :  V  =  140°18' ;  B  :  V  =  118°6'. 
It  fuses  into  a  magnetic  globule  with  crystalline  surface.  Melted,  in  powder, 
with  carb.  soda  and  nitre  in  a  platinum  spoon,  it  forms  an  alkaline  tungstate 
soluble  in  hot  water,  the  bases  remaining  for  the  greater  part  undissolved. 
The  solution  (which  at  first  is  green  from  some  dissolved  manganate  of  soda) 
when  boiled  with  hydrochloric  acid  and  a  piece  of  tin  or  zinc,  becomes  rapidly 
colourless,  ajad  then  assumes  a  deep  indigo-blue  colour. 


[124] 


TABLE   X. 

[Lustre  sub-metallic,  Infusible  ;  or  fusible  on  thinnest  edges  only.] 
A  —Yielding  Sulphur-reaction  with  carb.  soda  on  charcoal. 

(Zn  reaction}. 

SPHALERITE  OR  ZINC  BLENDE  :  Zn  67,  S  33.  Reg.;  H  3-5-4  ;  G. 
3-9-4-2.  Brown,  black,  red,  &c.;  streak  light-brown  ;  lustre  in  most 
examples,  non-metallic,  but  sub-metallic  in  many  dark  varieties. 

(Mn  reaction). 

ALABANDINE:  Mn  63-2,  S  36-8.  Reg.;  H.  3-5-4;  G  4;  black, 
brownish,  dark  steel-grey.  Streak  greenish,  Becomes  greyish-green 
on  ignition.  Scarcely  fusible,  but  slags  upon  surfa.ce  and  edges  in 
prolonged  heat.  No  sublimate  in  closed  tube. 

HAUERITE  :  Mn  46-2;  S.  53*8.  Reg.,  crystals  small,  parallel- 
planed  hemihedrons;  H  4;  G  3'46.  Dark  red-brown,  brownish 
black  ;  streak  brownish  or  brownish  red.  In  closed  tube  turns  green 
and  gives  sublimate  of  sulphur. 

B.— Magnetic  before  or  after  ignition. 

B*.— ANHYDROUS. 

MAGNETITE  (Magnetic  Iron  Ore)  :  Fe  72-41,  O  27-59,  =  Fe  O.  31, 
Fe2O3  69.  Reg.;  H  5-5-6-5;  G  4-9-5-2.  Iron  black,  with  black 
streak.  Strongly  magnetic,  often  showing  polarity.  Diamagnetite 
(of  Shepherd)  in  long  rhombic  prisms  is  probably  pseudomorphous 
after  Lievrite  (Dana).  Pseudomorphs  in  rhombohedrons,  after  Spa- 
thic iron  ore,  also  occur. 

FRANKLINITE  :  ZnO,  MnO,  FeO  ;  Fe203,  Mn203,  in  variable  pro- 
portions, but  giving  the  common  formula  RO,  R2O3.  Reg.;  H.  6-6 '5  ; 
G  5-0-5-1.  Black,  with  brownish  streak.  Often  strongly  magnetic. 

CHROMITE  (Chromic  Iron  Ore) :  FeO,  MgO,  CrO ;  A12O3,  Cr2O», 
Fe2O3  =  RO,  R2O3.  Reg. ;  H  5  5  ;  G  4-4-4-6.  Black,  brownish  or 
greenish  black  ;  streak  blackish  brown  to  nearly  black.  Sometimes 
magnetic. 

HEMATITE  (Red  Iron  Ore)  :  Fe  70,  O  30  (=  Fe2O3).  Henri-Hex., 
H  (ordinary  examples)  5-5-6-0;  G  5-5 -3.  Steely -red,  bluish-red, 
with  cherry-red  streak. 


MINERAL   TABLES  '. — X.  1  25 

ILMENITE  (Titaniferous  Iron  Ore):  Fe205  Ti208  in  variable  propor- 
tions. Henri-Hex.;  H  5'5-6  ;  G.  4-5-5 '3.  Black,  brownish-black ; 
streak  black  to  brownish-red.  See  Note  to  TABLE  VIII. 

B«—  YIELDING  WATER  ON  IGNITION  IN  BULB-TUBE, 

TURGITE  :  Fe2O8  94  7,  H2O  5-3.  H  5-55  ;  G  3-55-47 ;  black,  red- 
dish-brown, streak  dull  red.  Hydrohematite  is  identical  or  closely 
related. 

GOSTHITE  :  Fe'O8  90,  H'O  10.  Rh.;  H  5-5-5  ;  G  3'8-4'2.  Dark 
brown,  streak  brownish  yellow.  Lepidochrocite  and  Stilpnosiderite 
are  merely  varieties,  usually  containing  3  or  4  p.  c.  more  aq,  and 
thus  passing  into  ordinary  Brown  Iron  Ore. 

LIMONITE  or  BROWN  IRON  ORE  :  FeO3  8-5-6,  H2O  14-4.  Massive 
fibro-botryoidal,  &c.,  often  in  pseudomorphs  after  cubical  pyrites  and 
other  ferruginous  species.  H.  commonly,  5-5*5,  but  often  lower;  G 
3 -5-4.  Aspect  sub-metallic  in  some  varieties  only.  Brown,  brownish 
black ;  streak  brownish-yellow.  See,  also,  TABLE  XXIII. 

C.— Not  Magnetic  after  ignition. 

CV  -READILY  DISSOLVED  (IN  POWDER)  BY  HOT  HYDROCHLORIC  ACID, 
WITH  PRODUCTION  OF  CHLORINE  FUMES.* 

( B.  B.  strong  Mn  reaction). 

BRAUNITE  :  Mn  69-2,  O  30-8.  A  little  BaO  is  often  present  as  in 
most  manganese  ores,  and  many  impure  varieties  are  strongly  siliceous. 
Tet. ;  H.  5-5-6-5  ;  G  4-7-4-9.  Brownish-black,  with  similar  streak. 

HAUSMANNITE  :  Mn  72,  O  28,  but  BaO,  SiO2,  <fec.,  commonly  pre- 
sent as  impurities.  Tet. ;  H  5-5*5  ;  G.  4-7-4-9.  Black,  brownish 
black,  with  dark-brown  streak.  Braunite  and  Hausmannite  are 
comparatively  rare,  closely  related,  species.  The  crystals  are  small 
Tetragonal  octahedrons,  often  twinned. 

PYROLUSITE  :  MnO1.  Black ;  soils  ;  H  2-2-5.  Aspect  commonly 
metallic.  Fibrous.  See  TABLE  VIII. 

MANGANITE  :  Mn203  +  H2O.  Steel-grey,  iron-black  ;  H  3-5-4. 
Aspect  commonly  metallic  :  See  TABLE  VIII. 

PSILOMELANE  :  Iron-black,  dark  steel-grey ;  H.  5-6.  Gives  aq  in 
bulb- tube.  Aspect  commonly  metallic  beneath  dark  surface  tarnish. 
See  TABLE  VIII. 

*  Recognized  unmistakably  by  the  odour.  The  student  should  become  familiar  with  this 
by  warming  a  little  black  oxide  of  manganese  with  hydrochloric  acid. 


126  BLOWPIPE    PRACTICE. 

CHALCOPHANITE  :  MnO,  ZnO,  H2O.     Hemi-Hex. ;  H.  2-5  ;  G  3'9. 
Blue-black.     BB.  becomes  reddish  or  copper-coloured. 
(Strong  Cu  reaction}. 

CREDNERITE:  CuO  43,  Mn'2O8  57,  but  generally  impure  from 
presence  of  BaO,  SiO2,  &c.  Iron-black,  streak  black.  The  hydro- 
chloric acid  solution  is  green  or  bluish,  and  becomes  deep  blue  on 
addition  of  ammonia,  Mn203  gradually  precipitating. 

C'.— NO  CHLORINE  FUMES  PRODUCED  BY  TREATMENT  WITH  HYDROCHLORIC 
ACID.    Sp.  Gr,  OVER  2'0. 

(Decomposed  or  attacked  by  hot  sulphuric  acid}.* 

COLUMBITE  :  FeO,  MnO,  Nb2O5,  Ta2O6,  &c.  Rh. ;  H  6;  G  5-37-6-5. 
Iron-black,  brownish-black.  Streak  reddish  or  greyish-black.  Com- 
monly yields  a  little  tin  by  blowpipe  reduction. 

SAMARSKITE  :  YO,  FeO,  CeO,  U2O3,  Nb2O5,  Ta2O,  (fee.  Rh. ;  H 
5-6 ;  G  5-6-5-8  ;  black ;  streak  red-brown.  Diff.  fusible  into  steel- 
grey  mass.  Nohlite  (with  4-6  aq)  is  regarded  as  an  altered  variety. 

POLYCRASE  :  YO,  CeO,  ErO,  <fec.,  with  TiO2,  Nb2O5,  and  small  per- 
centage of  water.  Rh. ;  H  5-6  ;  G  5-5-15.  Black  ;  streak  brownish. 

^ESCHYNITE  :  CeO,  LaO,  YO,  &c.,  with  TiO2,  NbaO5,  ThO2,  &c., 
and  1  or  2  p.  c.  aq.  Rh. ;  H  5-5 '5 ;  G  5-5-25  \  black,  dark-brown  ; 
streak  brownish. 

MENGITE  :  Fe2O3,  ZrO2,  TiO2,  <fec.  Rh. ;  H  5-5-5  ;  G  5-48.  Black; 
streak  dark-brown. 

POLYMIGNITE  :  YO,  CaO,  FeO,  ZrO2,  TiO2,  &c.  Rh. ;  H  6-5.  G 
4-75-4-85.  Black  ;  streak  blackish-brown. 

PYROCHLORE  :  CaO,  CeO,  Na2O,  Fl,  ThO2,  Nb205,  TiO2,  &c.  Reg. ; 
H  5  ;  G  4-18-4-37.  Blackish  or  reddish-brown,  with  light  brown 
streak.  Fusible  on  edges  into  a  yellowish  slag.  Generally  yields  a 
little  aq  in  bulb  tube. 

PEROWSKITE  :  CaO  4O6,  TiO2  59*4.  Reg.,  with  cubical  cleavage. 
H  5-5;  G.  4-4-1.  Iron-black,  yellowish,  witn  metallic  adamantine 
lustre. 

WARWICKITE:  MgO,  FeO,  B2O8,  TiO2.  Clino-Rh. ;  H.  3-4;  G 
3-2-3-5.  Brown,  black,  reddish,  with  dark  streak.  When  moistened 
with  sulphuric  acid,  or  glycerine,  imparts  green  colour  to  flame. 

PITCHBLENDE — Slightly  attacked  by  sulphuric  acid.     See  below. 

*The  solution  diluted  slightly  and  boiled  with  addition  of  hydrochloric  acid  and  a  piece  of 
zinc  or  tin,  assumes  a  blue,  greenish,  or  violet  colour  (from  presence  of  Ta,  Nb,  or  Ti). 


MINERAL    TABLES: — X.  127 

( Not  attacked,  or  very  slightly  attacked,  by  sulphuric  acid). 
PITCHBLENDE  (Pitch  Uran  Ore,  Nasturan) :  TJO,  U2O3  (?)  with 
various  impurities.  Reg.  (?)  ;  H  (usually)  5-6 ;  G  6 -5-8.  Black, 
brownish -black,  with  black  or  dark  brown  streak.  Commonly  yields 
a  little  aq  on  ignition.  Decomposed  in  powder,  by  nitric  acid,  form- 
ing a  yellow  solution.  See  TABLE  XXIII. 

CASSITERITE  (Tinstone)  :  Sn  78-6,  O  21'4.  Tet.  ;  H  6-7 ;  G  6-5- 
7'1.  Black,  brown,  greyish, 'dec.  Lustre,  as  a  rule,  non-metallic: 
See  TABLE  XXIV.  BB.,  with  reducing  flux,  yields  metallic  tin. 

TANTALITE:  FeO,  MnO,  Ta2O5,  Nb2O5,  &c.  Rh. ;  H  6-6-5;  G  6-3-8 
(usually  about  7).  Iron-black ;  streak  dark-brownish.  Commonly 
gives  BB  with  reducing  flux  a  little  tin.  TAPIOLITE  is  apparently  a 
Tetragonal  Tan  tali  te. 

YTTROTANTAUTE  :  YO,  ErO,  FeO,  CaO,  Ta205,  WO3,  «fec.,  with  4-6 
p.  c.  aq,  but  the  latter  probably  a  product  of  alteration.  Rh.  ;  H 
5-5-5  ;  G  (as  regards  the  black  sub-metallic  varieties)  5-4-5-7;  black, 
brownish-yellow.  Becomes  yellow  and  yields  aq  in  bulb-tube.  With 
reducing  flux  gives  generally  a  little  tin.  HJELMITE  is  a  related 
tantalate,  containing  SnO2,  WO3,  &c.  G  5'82.  Black. 

FERGUSONITE  :  YO,  ErO,  CeO,  FeO,  <fcc.,  with  Nb2O  and  Ta205, 
and  1-7  p.  c.  aq.  Tet.;  H.  5-5-6;  G  5-6-5-9.  Black,  blackish- 
brown,  with  pale  brown  streak.  Tyrite  and  Bragite  are  varieties. 

EUXENITE  :  YO,  CeO,  UO,  &c.,  with  Tio2,  Nb'05,  and  2-3  p.  c.  aq. 
Rh. ;  H.  6-5  ;  G  4*6-5 ;  black,  brownish-black;  streak,  red-brown. 
Burns  brownish-yellow  and  yields  aq  by  ignition  in  bulb-tube. 

[NOTE. — The  Nio-tantalates  and  Nio-titaniates  of  this  and  the  preceding 
section  are  for  the  greater  part  very  imperfectly  known,  and  all  are  of  rare 
occurrence.  Several  have  probably  little  claim  to  rank  as  distinct  species.] 

RUTILE  :  Ti  61,  O  39.  Tet. ;  Crystals  commonly  prismatic,  and 
often  in  geniculated  twins  ;  sometimes  acicular.  H  6-6-5  ;  G  4-2-4-3  ; 
red,  with  metallic-adamantine  lustre ;  more  rarely  black  (Nigrine),  or 
yellowish  ;  streak  pale  brown. 

ANATASE  or  OCTAHEDRITE  :  Ti  61,  O  39.  Tet.,  crystals  commonly 
pyramidal,  of  small  size.  H  5-5-6 ;  G  3*8-4  ;  dark  indigo-blue, 
greyish,  brownish,  with,  in  general,  adamantine  lustre. 

BROOKITE  :  Ti  61,  O  39.  Rh. ;  H  5-5-6 ;  G  4-4-25.  Hair-brown, 
reddish,  yellowish,  black  (Arkansite).  Comparatively  rare. 


128  BLOWPIPE    PRACTICE. 

C«.— NOT  ATTACKED  BY  ACIDS.    SPECIFIC  GRAVITY  UNDER  2. 

ANTHRACITE  :  Carbon,  with  small  amounts  of  H,  O,  and  N  ; 
hygroscopic  moisture,  and  inorganic  matter  or  "ash"  (1  to  over  20 
p.  c.)  being  also  present  in  most  examples.  H  3  (or  2-5-3-25) ;  G 
1  -2-1  -8  ;  black,  often  iridescent  in  places  ;  streak  greyish-black. 


NOTE  ON  TABLE  X. 

Excluding  the  manganese  ores,  Pyrolusite  and  Manganite,  the  lustre  of 
which  is  essentially  metallic  (see  TABLE  VIII),  the  more  commonly  occurring 
minerals  of  this  table  comprise  the  following  species  :  (1)  the  iron  ores,  Mag- 
netite, Franklinite,  Chromite,  Haematite,  Ilmenite,  and  Limonite  ;  (2)  The 
sulphide  Sphalerite  or  Zinc  Blende  ;  (3)  The  tin  ore,  Cassiterite  ;  (4)  The  two 
forms  of  Titanic  anhydride,  Rutile  and  Anatase  ;  and  (5)  the  coal  variety, 
Anthracite. 

As  regards  the  iron  ores,  Magnetite  and  Franklinite  are  strongly  magnetic 
in  their  natural  condition  ;  the  others  occasionally  are  feebly  magnetic,  but  all 
attract  the  magnet  strongly  after  ignition  in  the  R.  F.  Magnetite  is  frequently 
in  large  masses,  and  also  in  regular  octahedrons  and  rhombic  dodacahedrons. 
Both  colour  and  streak  are  black.  Thin  splinters  may  be  fused  at  the  extreme 
point.  Franklinite  is  commonly  in  small  rounded  masses  imbedded  in  crystal- 
line limestone  with  red  zinc  ore,  &c.,  less  commonly  in  cubes  and  octahedrons, 
or  in  large  masses.  Its  streak  is  reddish-brown.  BB,  with  carb.  soda  it 
gives  Mn  and  Zn  reactions.  Some  examples  are  said  to  be  slightly  magnetic 
only.  Chromite  is  almost  always  in  granular  masses  of  a  black  colour.  Its 
sp.  gr.  is  much  lower  than  that  of  Magnetite  and  Franklinite  ;  and  it  forms 
with  Borax  a  fine  green  glass,  by  which  it  is  readily  distinguished  from  the 
above  species.  The  student  must  remember,  however,  that  mixtures  of  these 
iron  ores  often  occur. 

Haematite  is  essentially  distinguished  by  its  cherry-red  streak  or  powder. 
It  is  commonly  in  granular,  slaty,  or  fibro-botryoidal  masses.  Its  crystals 
generally  present  a  strongly  marked  metallic  lustre.  They  are  mostly  rhom- 
bohedral  combinations  with  largely  developed  basal  plane  (See  note  to  TABLE 
VIII.)  Ilmenite  is  a  titaniferous  haematite,  usually  of  dark  colour  and  dark 
streak.  Its  crystals  resemble  those  of  haematite,  but  the  interfacial  angles  are 
slightly  different.  It  is  best  distinguished  by  the  amethystine  colour  pro- 
duced in  its  hydrochloric  acid  solution  by  boiling  with  tin  or  zinc. 

Limonite  or  Brown  Iron  Ore  is  distinguished  by  its  ochre-yellow  streak,  and 
by  yielding  water  in  the  bulb-tube.  It  is  commonly  in  dark  brown  masses  of 
granular  or  fibrous  structure.  The  surface  is  often  iridescent.  Frequently 
also  it  is  found  in  coarse,  brown  cubes,  and  other  pseudomorphous  crystals, 
after  iron  pyrites.  Light-brown  examples  also  occur,  but  these  present  a  silky 
or  other  non-metallic  aspect.  (See  TABLE  XXIII). 


MINERAL    TABLES: — X.  129 

Zinc  Blende  is  at  once  distinguished  from  other  minerals  of  the  Table — the 
very  rare  manganese  sulphides  excepted — by  the  sulphur  reaction  which  it 
yields  with  carb.  soda.  Its  powder  warmed  with  hydrochloric  acid  also  emits 
the  odour  of  sulphureted  hydrogen.  Commonly  in  cleavable  masses  of  a  black- 
brown,  dark -red  or  yellowish  colour,  or  in  groups  of  crystals  (mostly  tetrahe- 
drons, or  combinations  of  rhombic  dodecahedron  and  tetrahedron)  of  the 
Regular  System.  A  dark  ferruginous  variety  (which  becomes  magnetic  after 
ignition)  has  been  named  Marmatite  ;  and  a  cadmiferous  var.  (mostly  in  dark 
sub-fibrous  masses)  is  termed  Przibramite.  (See  also  the  note  to  TABLE  XVI.) 

Cassiterite  or  Tinstone  scarcely  belongs  to  the  present  table,  as  in  most 
examples  the  lustre  is  essentially  non-metallic.  Its  great  weight  and  hardness, 
tetragonal  (often  twinned)  crystallization,  and  its  property  of  yielding  tin 
globules  by  reduction  with  mixture  of  carb.  soda  and  borax,  are  its  more 
distinctive  characters. 

Rutile  and  Anatase  (two  of  the  natural  representatives  of  binoxide  of  Ti- 
tanium, the  comparatively  rare  Brookite  being  a  third  representative  of  that 
compound),  have  in  most  examples  a  non-metallic  (adamantine)  lustre,  with  a 
certain  degree  of  translucency.  But  some  examples  are  opaque.  Rutile  resem- 
bles Cassiterite  (and  also  Zircon,  TABLE  XXIV.)  in  its  crystallization.  The 
crystals  are  commonly  composed  of  two  square  prisms  (forming  a  pseudo- 
8-sided  prism)  with  pyramidal  terminations.  The  prism-planes  are  striated 
vertically  in  most  cases,  and  the  basal  plane  (as  in  Zircon)  is  constantly 
wanting.  Geniculated  twins  are  common.  The  colour  is  generally  dark 
brownish-red  or  blood-red,  but  light-brown  and  other  tints  also  occur.  Ana- 
tase occurs  in  small  pyramidal  crystals,  usually  composed  of  two  or  several 
square  octahedrons,  the  more  common  one  having  the  angle  over  a  polar  edge 
=  97°50',  and  over  a  middle  edge  =  136°36'.  Prism  planes  and  basal  plane 
are  also  occasionally  present,  and  some  crystals  are  tabular  from  predominance 
of  the  latter.  The  colour  is  usually  indigo-blue,  brown,  or  greyish-blue.  Both 
Rutile  and  Anatase,  when  fused  in  fine  powder  with  caustic  potash  (or  with 
carb.  soda  and  borax),  are  attacked  or  dissolved  by  hydrochloric  acid,  the 
diluted  solution  becoming  of  a  deep  amethystine  tint  when  boiled  with 
metallic  tin. 

Anthracite  is  at  once  distinguished  from  other  minerals  of  the  Table  by  its 
low  specific  sp.  gr.  j[l'2-l-8).  The  lustre,  moreover,  is  properly  non-metallic. 

XXV, 

10 


[1301 


TABLE    XI. 

[Aspect  non-metallic.     Readily  inflammable :  *  burning  with  sulphurous  or 
alliaceous  odour.] 

A.— Burning  with  sulphurous  odour. 

(Streak^  yellow J. 

NATIVE  SULPHUR  :  Eh. ;  H  1-5-2-5  ;  G  1-9-2-1 ;  yellow,  brownish, 
reddish-yellow.  See  Note,  below. 

(Streak,  red  or  brovm). 

CINNABAR  :  Hg  68-2,  S  13-8.  Hemi-Hex. ;  H  2-2-5  ;  G-  (normally) 
8-9,  but  often  lower  in  dark  carbonaceous  varieties.  Red  with  red 
streak;  but  sometimes  brown  from  admixture  with  carbonaceous 
matter. 

IDRIALINE  :  A  mixture  of  Cinnabar  with  earthy  matter  and  C*H>. 
Brownish-black  ;  streak  brown  or  reddish.  H  1-1-5  ;  G  1-4-1-6. 

KERMESITE  :  (Sb,  S,  O).  Inflammable  in  some  varieties  only  ; 
mostly  fibrous  or  acicular.  G  4'5.  See  TABLES  IX,  XY.  BB,  copi- 
ous antimonial  fumes. 

(Streak,  black). 

COVELLINE  :  Cu  65-46,  S  33-54.  Hex. ;  H  1-5-2 ;  G  4-4-6.  Bark 
coppery-blue,  blackish-blue.  BB,  copper  reaction. 

B.— Burning  with  alliaceous  (arsenical)  odour. 

(Colour,  yellow). 

ORPIMENT  :  As  6,  S  39,  Rh. ;  H  1-5-2  ;  G  3-4-3-5.  Bright  yellow, 
commonly  with  metallic-pearly  lustre ;  streak  yellow.  In  thin  pieces, 

flexible. 

(Colour,  red). 

REALGAR  :  As  78,  S  30.  Clino-Rh.  H  1-5-2  ;  G  3-5-3-6.  Red, 
streak  orange-yellow. 

NOTE  ON  TABLE  XI. 

The  principal  minerals  of  this  Table  are  N.  Sulphur,  Orpiment,  Realgar,  and 
Cinnabar.  The  latter  is  distinguished  more  especially  by  its  high  sp.  gr.  and 
ita  red  streak. 

*  To  test  this  property,  a  small  piece  of  the  mineral  may  be  taken  up  by  the  steel  forceps  and 
held  for  an  instant  againit  the  edge  of  a  Bunsen-flame  or  the  flame  of  a  common  candle. 


MINERAL    TABLES  I XI.  131 

Native  sulphur,  when  crystallized,  is  commonly,  in  acute  rhombic-octahe- 
drons of  small  size.  It  occurs  generally  in  indistinct  druses,  massive  or 
efflorescent  on  pyrites,  &c.  It  melts  into  red-brown  drops  which  become  pale 
yellow  on  cooling.  From  Orpiment,  which  is  equally  inflammable,  it  is  dis- 
tinguished by  its  low  sp.  gr.  and  by  the  absence  of  arsenical  odour  during 
combustion. 

Orpiment  is  occasionally  in  small  prismatic  crystals,  but  occurs  generally  in 
foliated  or  other  examples.  It  dissolves  entirely  in  caustic  potash,  and  is  re- 
precipitated  from  the  solution  by  hydrochloric  acid. 

Realgar  is  distinguished  from  Cinnabar  by  its  orange-yellow  streak,  as  well 
as  by  its  lower  sp.  gr. ,  and  the  arsenical  odour  evolved  on  combustion.  Its 
crystals  are  small  Clino-Rhombic  prisms  with  largely  developed  basal  plane, 
but  are  generally  in  druses,  or  otherwise  indistinct.  Most  commonly  it  occurs 
in  granular  or  other  masses.  In  caustic  potash  it  leaves  a  brown  residuum  of 
sub-sulphide.  Otherwise  like  Orpiment. 

Cinnabar  is  the  essential  ore  of  mercury.  Under  normal  conditions  it  pre- 
sents a  scarlet  red  colour  (whence  its  old  name  of  Native  Vermilion)  and  un- 
changed streak,  but  the  surface  is  usually  brownish,  and  many  examples  are 
dark-brown  from  intermixed  earthy  or  bituminous  matter  (Liver  Ore,  &c.) 
The  crystals  are  combinations  of  rhombohedrons  and  hexagonal  prism,  the 
triangular  basal  plane  being  especially  apparent.  Tetartohedral  forms  have 
been  recognized,  but  in  general  the  crystals  are  small,  and  more  or  less  in- 
distinct. Cinnabar  occurs  more  commonly  in  granular  masses,  and  occasionally 
in  thin  coatings  or  incrustations.  Metallic  mercury  is  easily  sublimed  from  it 
by  ignition  with  dry  carb.  soda,  iron  filings  or  other  reducing  agents,  in  a  small 
flask  or  test-tube.  Scarcely  attacked  by  caustic  potash,  or  by  nitric  or  hydro- 
chloric acid.  Soluble  in  aqua  regia. 


[132] 


TABLE    XII. 

[Aspect  non-metallic.     Inflammable  in  candle  flame,  burning  with  bituminous 
or  aromatic  odour.] 

A  —Coaly,  ligneous,  or  pitch-like  aspect.    Burning  with 
bituminous  odour. 

BITUMINOUS  COAL  :  C  74-96,  H  0-5-5-5,  O  3-20.  Black,  often  iri- 
descent ;  streak,  black.  H  2-2-5  ;  G  1-2-5. 

LIGNITE  or  BROWN  COAL:  C  55-80;  H  3-6 ;  0  17-27.  Dark- 
brown  or  black  (jet)  with  brown  streak.  H  2-2-5  ;  G  1-2-1.4.  Mas- 
sive, ligniform,  sometimes  foliated  (Paper  Coal),  and  earthy.  Imparts 
a  brown  colour  to  caustic  potash.  "Torbarnite"  is  sometimes  referred 
to  this  variety,  but  it  is  properly  a  mere  bituminous  shale. 

BITUMEN  or  ASPHALT  :  C,  H,  O.  Black,  greenish-black.  H  0-5- 
2-0;  G  1-0-1*2.  Semi-fluid  or  pasty  in  ordinary  examples,  also  in 
stalactitic  and  other  more  or  less  brittle  masses  with  conchoidal 
fracture.  Passes  into  Petroleum. 

ALBERTITE  :  C,  H,  N,  O.  Black,  highly  lustrous,  brittle.  H  2- 
2-5  ;  G  1-1  -1.  Scarcely  attacked  by  alcohol,  but  partially  dissolved 
by  oil  of  turpentine.  STELLARITE  .and  GRAHAMITE  are  related  sub- 
stances. 

ELATERITE  (Elastic  Bitumen) :  C,  H,  O.  Dark-brown  or  black. 
Soft  and  flexible,  resembling  caoutchouc.  Passes  into  ordinary  bitu- 
men. G  0-8-1-2.  DOPPLERITE  is  a  closely  related  substance. 

B-— Resinous  (or  when  dark  coloured  somewhat  coaly)  in 
aspect,  but  burning  with  aromatic  (non-bituminous)  odour. 

PIAUZITE  :  dark-brown,  with  yellowish -brown  streak.  H  1-5-2; 
G  1-18-1-22.  Soluble  in  ether  and  in  caustic  potash.  Pyroretine  is 
apparently  related. 

.AMBER  (Succinite,  Bernstein)  C,  H,  O  (=  C  79,  H  10-5,  O  10-5?). 
Yellow,  brownish,  reddish,  greyish- white.  Mostly  in  nodular  masses. 
H  2-2-5  ;  G  1-0-1-1.  Electric  by  friction. 

BETINITE,  KRANTZITE,  IXOLITE,  SIEGBURGITE,  PYROPISSITE,  and 
other  obscurely  known  amber-like  substances,  belong  also  to  this 
group. 


MINERAL  TABLES: — xn.  133 

C.— Wax-like  in  aspect. 

OZOKERITE  (Keftgil):  Essentially  C  85-7,  H  14-3  (2-3  per  cent.  O 
present  in  some  examples).  Green,  brownish  (by  transmitted  light, 
yellowish  or  red).  Very  soft,  pasty ;  G  0'95.  Emits  per  se  an  aro- 
matic odour.  Easily  sol.  in  oil  of  turpentine.  Scarcely  or  slowly  sol. 
in  ether  and  alcohol. 

PARAFFINS  —  URPETHITE — HATCHETTINE —  GEOCERITE—  GEOMY- 
GERITE — EUOSMITE  :  Greyish- white  to  brownish  yellow,  soft  wax-like 
substances,  more  or  less  readily  soluble  in  ether. 

HARTITE.- — A  white  or  brownish  crystalline,  wax-like  substance, 
soluble  in  ether.  See  under  D,  below. 

D.— Crystalline  in  aspect- 

FICHTELITE  :  C  87-13,  H  12-87.  In  white,  pearly,  crystalline 
laminae,  soluble  in  ether.  After  fusion,  becomes  again  crystalline 
on  cooling.  TEKORETINE  (Clino-Rhombic)  is  identical. 

SCHEERERITE  (Konleinite) :  C  and  H.  In  white  acicular  or  lamel- 
lar crystals  (Clino-Rhoinbic).  G  1-1-2.  Dissolves  readily  in  ether, 
but  rapidly  separates  again. 

HARTITE  :  C  and  H.  In  soft  paraffine-like,  white  or  brownish 
crystalline  lamellae,  or  small  (anorthic)  crystals.  H  1  -0-1  -5 ;  G 
slightly  over  I'O.  Largely  soluble  in  ether,  BOMBICCITE  is  a  related 
crystalline  (anorthic)  compound,  but  is  said  to  contain  nearly  15  per 
cent.  0,  Easily  soluble  in  ether  and  in  alcohol. 


NOTE  ON  TABLE  XII. 

The  substances  included  in  this  Table  are  essentially  hydro-carbon  com- 
pounds, probably  in  great  part  (or  wholly,  according  to  the  common  view), 
of  organic  origin.  The  absolutely  organic  nature  of  asphalt  and  other  bitu- 
minous substances,  remains,  however,  yet  to  be  proved.  Many  other  com- 
pounds enumerated  by  chemists  might  have  been  referred  to  in  the  Table ;  but 
the  composition  of  these  hydro-carbons  appears  to  be  more  or  less  variable, 
and  their  physical  characters,  in  most  instances,  cannot  be  very  rigorously 
defined.  The  more  common  representatives  of  the  Table  comprise — Bitumin- 
ous Coal,  Brown  Coal,  and  Amber,  The  latter  occurs  mostly  in  nodular  or 
irregular  masses  of  a  light  or  deep  yellow  colour,  but  is  sometimes  greyish- white 
or  brownish,  and  frequently  clouded.  Some  examples  are  quite  transparent, 
others  only  translucent,  and  many  are  quite  opaque.  Leaves  and  insects  are 


134  BLOWPIPE    PRACTICE. 

frequently  enclosed  in  these  nodules,  and  thus  amber  is  usually  regarded  as  a 
coniferous  gum  or  resin  of  Cainozoic  age.  Fraudulent  imitations  of  insect- 
holding  amber  are  often  imposed,  however,  on  the  unwary.  Like  other  resin- 
ous bodies,  amber  is  rendered  strongly  electrical  by  friction. 

Bituminous  coals  generally  leave,  by  ignition  in  closed  vessels,  a  semi -fused 
agglutinated  coke.  These  are  commonly  known  as  "caking  coals."  In 
brown  coals,  proper,  the  coke  remains  unf used.  In  all  kinds  of  coal,  sulphur 
(from  pyrites,  and  occasionally  from  gypsum,)  is  present  more  or  less  ;  and  all 
coals  contain  a  certain  amount  of  intermixed  earthy  matter  or  "  ash."  This 
latter  may  vary  from  2  or  3  to  10  or  15  per  cent ,  but  many  coals  pass  into 
coal  shales,  when  the  amount  of  earthy  matter  (essentially  a  silicate  of  alu- 
mina) may  exceed  50  per  cent.  All  coals,  moreover,  contain  hygroscopic  mois- 
ture, varying  (according  to  conditions  of  exposure,  &c.,)  from  about  3  or  4,  to 
over  10  or  12  per  cent.,  or  higher  in  many  brown  coals.  See  Appendix  to 
"  Blow-pipe  Practice,"  page  76,  On  the  Examination  of  Coals  by  the  Blowpipe. 


[135] 


TABLE    XIII. 

[Non-metallic  aspect .  Readily  sol.,  BB.,  in  phosphor-salt.  Effervescing  in 
diluted  hydrochloric  acid,  (N,  B. — The  acid  in  some  cases  must  be 
gently  heated.)] 

A,— Yielding  metallic  globules,  per  se,  or  with  carb.  soda  on 

charcoal. 

A*— ANHYDROUS  SPECIES.     NO  WATER,  OR  PAINT  TRACES  ONLY,  IN  BULB- 
TUBE. 

(No  reaction  of  8  or  Cl). 

CERUSSITE  :  PbO,  83-52,  CO2  16-48  =  Pb  77'6.  Rh.  ;  H  3-3-5  ; 
G  (normally)  6 -4-6-6,  but  lower  in  impure  earthy  varieties.  Colour- 
less, or  grey,  nearly  black,  yellowish,  &c.;  streak  white.  IGLEASITE 
is  a  zinc-holding  variety. 

PLUMBO-CALCITE  :  =  Plumbiferous  var.  of  Calcite  or  Calc  Spar, 
TARNOWITZITE  =  Plumbiferous  var.  of  Arragonite.  G  about  2-8. 
Both  give  a  lead  sublimate  on  charcoal,  but  metallic  globules  are  not 
readily  obtained. 

(8  reaction). 

LEADHILLITE  :  PbO,  CO2  72-56,  PbO,  SO3  27-44  =  Pb  75.  Eh. ; 
H  2-5-3;  G  6'2-6'6.  Yellowish-white,  grey,  brownish,  &c.,  streak 
white.  SUSANNITE  is  a  supposed  rhombohedral  variety  (G  6-55). 
MAXITE  is  probably  an  altered  var.,  containing  a  small  percentage  of 
water. 

CALEDONITE  :  PbO,  CuO,  SO3  (CO2  by  alteration  or  admixture). 
Light-green.  See  Table  XYI.) 

(Cl  reaction). 

PHOSGENITE  (Kerasine) :  PbO,  CO2  49,  PbCP  51,  =  Pb  73-8. 
Tet. ;  H  2-5-3;  G  6-6*3.  Yellowish-white,  grey,  yellow,  green; 
streak  white. 

A*— YIELDING  WATER  ON  IGNITION. 

(  Cu  reaction). 

MALACHITE:  CuO  71-95,  CO2  19-90,  IPO  8-15.  Clino-Rh.,  but 
rarely  crystallized.  H  1-0-4;  G  3-7-4.  Green,  often  zoned  in  dif- 
ferent shades ;  streak  light-green.  Some  varieties  are  calcareous. 
ATLASITE  is  a  variety  containing  copper  chloride. 

AZUKITE  (Chessylite) :  CuO  69'2,  CO2  25-6,  HaO  5-2.  Clino-Rh.; 
H  1-4;  G  3*7-3-8.  Blue,  paler  in  the  streak. 


136  BLOWPIPE   PRACTICE. 

See  also  TIROLITE,  Table  XIV,  many  examples  of  which  contain 
intimately  intermixed  carbonate  of  lime.  Green  or  blue  radiated 
masses,  or  earthy.  BB,  strong  arsenical  odour. 

(Cu  and  Zn  reactions). 

AURICHALCITE  :  CuO  28,  ZnO  46,  CO216,  H20  10  (?).  Acicular 
or  fibrous.  H  2  ;  G  about  3*3.  Green  or  bluish  j  streak  paler. 
BURATITE  is  a  calcareous  variety. 

(  Bi  reaction). 

BISMUTITE  :  BiO,  CO,  H'0.  H  4-4-5  (?)  G  6-8-6-9  (?).  Yellow, 
grey,  green ;  streak  paler.  A  doubtful  species,  more  or  less  variable 
in  characters  and  composition. 

B.— No  metallic  globules  obtained  by  fusion  with  carb  soda 

on  charcoal. 

BI— ANHYDROUS   SPECIES.     NO  WATER,  OR  TRACES  ONLY,  IN  BULB  TUBE. 

(NoTE: — The  presence  of  Ca,  Ba,  Sr,  singly  or  together,  in  carbonates  of 
this  group,  is  very  readily  ascertained  by  a  small,  direct  vision  spectroscope. 
See  Outline  of  Blowpipe  Practice,  pp.  55,  57. 

f  Magnetic  after  ignition. 

SIDERITE  (Spathic  Iron  Ore)  :  FeO  62,  CO238,  =  Fe  48-2  ;  part  of 
the  FeO,  however,  often  replaced  by  MgO,  MnO,  CaO.  Herui-fiex.  ; 
H  3  5-4 -5  ;  G  3*7-4-1 ;  yellowish-grey,  yellow,  brown,  olive-green, 
&c.,  streak  paler.  SPHEROSIDERITE  is  a  fibrous-spherical  variety 
from  trap  rocks ;  CLAY-!RONSTONE,  BLACK  BAND,  &c.,  are  impure 
argillaceous  or  bituminous  varieties  from  coal  strata.  SIDEROPLE- 
SITE,  MESITINE  and  PISTOMESITE  (G  3-3-3-6)  are  crystalline  magne- 
sian  vars. ;  and  OLIGON  SPAR,  a  variety  containing  25*5  p.  c.  of  MnO 
CO2.  In  the  typical  rhombohedron,  R  :  R  =  107°,  whilst  in  the  Mg 
and  Mn  examples  it  varies  from  107°3'  to  about  107°18'.  Crystals, 
however,  commonly  present  curved  planes. 

ANKERITE  :  (CaO,  MgO,  MnO,  FeO)  CO2.  Hemi-Hex.,  with  RR 
about  106°  12'.  White,  yellowish,  brownish ;  streak,  in  un weathered 
examples,  white.  H  3-4;  G  2-9-3-3.  Merges  into  Siderite,  Calcite, 
and  Dolomite. 

See  also  dark-coloured  varieties  of  MAGNESITE  and  DOLOMITE. 

ft  Not  magnetic  on  ignition ,  and  no  marked  alkaline  reaction. 


MINERAL    TABLES  I — XIII.  137 

(Strong  reaction  of  Mn). 

RHODOCHROSITE  (DIALLOGITE,  MANGANESE  SPAR)  :  MnO  61-74, 
CO2  38-26,  but  MnO  often  in  part  replaced  by  CaO  and  MgO.  Hemi- 
Hex,  with  R  :  R  (normally)  106°5'.  H  3'5-4'5  ;  G-  3-3-3-6.  Rose- 
red,  pink-brownish  when  weathered ;  streak  very  pale  red,  reddish- 
white.  Blackens  on  ignition.  RCEPPERITE  is  a  calcareo-magnesian 
variety. 

(Co  reaction). 

SPH^ROCOBALTITE  (Cobalt  spar)  :  CoO  63,  CO2  37.  H  4  ;  G  4-0- 
4*1.  In  spherical  concretions,  black  externally,  red  within.  A 
doubtful  species. 

(Zn  reaction). 

SMITHSONITE  (Calamine,  Zinc  Spar) :  ZnO  64-8,  Co235-2.  Hemi- 
Hex.,  with  R :  R  =  107°40'.  H  5;  G  4-4-5.  Colourless,  pale- 
greyish,  greenish,  brownish ;  streak,  white.  Many  varieties  contain 
FeO  and  MriO.  HERRERITE  is  a  cupreous  variety. 

f  |f  Alkaline  reaction,  after  strong  ignition. 
(Ba  reaction :  flame  coloured  pale-green). 

WITHERITE  :  BaO  77-67,  CO2  22-33.  Rh.,  with  pseudo-hexagonal 
aspect.  H  3-3-5  ;  G  4"2-4*4.  Colourless,  pale-grey,  yellowish ; 
streak  white.  BB,  entirely  soluble  in  carb.  soda. 

ALSTONITE  (Bromlite) :  BaO,  CO2  66-33  +  CaO,  CO2  33-67.  Rh.; 
H4-4-5;  G  3-6-3-8.  Colourless,  greyish ;  streak  white.  BB,  only 
in  part  sol.  in  carb.  soda. 

BARYTO-CALCITE  :  Composition  and  general  characters  as  in  ALSTO- 
NITE ;  but  crystallization  Clino-Rhombie,  with  V  :  V  84°  5 2'. 

(Sr  reaction:  crimson  flame-coloration). 

STRONTIANITE  :  SrO  70-27,  CO2  29-73.  Rh.  (V  :  V  =  117Q19') ; 
H  3*5;  G  3-6-3-8.  Colourless,  greenish,  yellowish,  &c.;  streak 
white.  Some  varieties  are  more  or  less  calcareous ;  others  (Strom- 
nite)  contain  baryta, 

(Ga  reaction :  flame,  after  prolonged  ignition  of  test- substance,  coloured  red). 
CALC  SPAR  or  CALCITE  :  CaO  56,  CO244.  Hemi-Hex,  with  rhom- 
bohedral  cleavage  (R  :  R  105°5' ;  or  varying  from  about  105  to  105° 
18',  part  of  the  CaO  being  commonly  replaced  by  MgO,  FeO,  &c). 
H  (normally)  3,  but  often  lower;  G  2*6-2 -8.  Colourless  or  variously 
tinted  ;  streak  white.  See  Note  below. 


138  BLOWPIPE   PRACTICE. 

DOLOMITE  (Bitter  Spar)  :  CaO,  CO2  54-35,  MgO,  C0«  45-65,  but 

often  more  or  less  ferruginous,  &c.  Hemi-Hex  (R  :  R  106*15' 106° 

20');  H  3-5-4;  G  2-8-3-0.  Colourless,  yellowish,  brownish,  &c.  The 
varieties  containing  FeO  are  commonly  called  Brown  Spar.  Through 
these  there  is  a  complete  transition  into  Aiikerite  and  Siderite. 
GURHOFIAN  and  KONITE  are  impure  silicious  varieties,  with  H  = 
4-5-5-5. 

ARAGONITE:  CaO  56;  CO2  44.  Rh.  (V  :  V  116*10');  H  3-5-4 ; 
G  2-7-3-0,  normally  2 -9 4.  Colourless,  light-yellow,  brown-violet, 
reddish,  greenish ;  streak  white.  Commonly  falls  into  powder  on 
ignition.  Some  examples  contain  a  small  percentage  of  strontia. 
Flos  Ferri  is  a  coralloidal  var.,  accompanying  iron  ore  at  certain 
localities.  TARNOVITZITE  is  a  highly  plumbiferous  variety. 

(Mg  reaction :  No  flame  coloration,  if  pure  ;  reddened  by  ignition  with  cobalt- 

solution). 

MAGNESITE  :  MgO  47'62,  CO2  52-38,  but  part  of  MgO  commonly 
replaced  by  FeO,  CaO,  &c.  Hemi-Hex.  (R  :  R  107°16'— 107*29'). 
H  3-4-5,  or  lower;  G  2-8-3-1.  Colourless,  snow-white,  yellow, 
greyish,  <fcc. ;  streak  white.  GIOBERTITE  is  merely  crystallized 
Magnesite. 

B*—  HYDROUS  SPECIES,  YIELDING  WATER  BY  IGNITION  IN  CLOSED  TUBE. 

f  Soluble  or  partly  sol.  in  water. 

NATRON:  Na2O  22,  CO2  15,  H2O  63.  Clino-Rh.  (V:  V  =  79*41'), 
but  chiefly  earthy  and  efflorescent.  H  1-1*5  ;  G  1-4-1-5.  Normally 
colourless. 

THERMONATRITE  :  Na2O  50,  CO2  35-5,  H2O  14-5.  Rhombic, 
mostly  in  rectan.  tables ;  H  1-5;  G  1-5-1-6.  Normally  colourless. 

TRONA:  Na2O  38,  CO2  40,  H'O  22.  Clino-Rh.;  H  2-3;  G  2-1-2-2. 
Normally  colourless.  Commonly  mixed  with  NaCl. 

GAYLUSSITE  :  Na2O  CO2  35-50 ;  CaO,  CO2  34-08,  H2O  30-42.  Clino- 
Rh  (V  :  V  68-51').  H  2-5 ;  G  19-4 ;  colourless.  Slowly,  and  only 
in  part,  soluble  in  water. 

ft  Insoluble  in  water.  Giving  BB  with  borax  an  uncoloured  or  very 
lightly-tinted  glass. 

GAYLUSSITE  :  Partly  sol.     See  above. 

HYDROMAGNESITE  :  MgO  44,  CO2  36-2,  H2O  19-8.  Clino-Rh.,  or 
Rh.  (V  :  V  87* — 88°),  but  commonly  massive  or  earthy;  white; 


MINERAL  TABLES: — xm.  139 

H  1-3-5  ;  G  2-1 4-2-18.  Some  of  the  earthy  varieties  give  only  4  or 
5  p.  c.  water  on  ignition.  BAUDISSERITE  is  an  impure  silicious  var. 
LANCASTERITE,  according  to  Smith  and  Brush,  is  a  mixture  of  Hydro- 
rnagnesite  and  Brucite.  Hydrodolomite,  in  white  or  yellowish 
spherical  masses  from  Vesuvius,  is  a  compound  of  Hydromagnesite 
with  Calcite  or  Dolomite. 

HYDROZINKITE  (Zink  Bloom):  ZnO  75-24,  CO  13-62,  HX)  11-14. 
In  white  or  yellowish  earthy  or  oolitic  masses,  or  efflorescent  on  zinc 
ores.  G  3-25. 

DAWSONITE  :  A  compound  (or  mixture  produced  by  alteration  1)  of 
APO,  CaO,  Na'O,  CO2  and  H2O.  In  colourless,  thin-bladed  aggre- 
gations or  coatings  on  compact  trachyte,  Montreal.  H  3 ;  G  2 -4. 
HOVITE,  in  white  earthy  crusts,  is  apparently  related  in  composition. 

TENGBRITE  :  YO,  CO2,  H2O.  In  white  or  yellowish  earthy  crusts 
on  certain  examples  of  Gadolinite. 

LANTHANITE  :  LaO  52-6,  CO  21-3,  IPO  26-1.  Rh.  (Y  :  Y  92°50' 
— 94°),  generally  tabular.  H  2'5-3'0;  G  2*67  ;  greyish  or  yellowish- 
white,  pale  red.  BB,  with  borax,  a  pink  or  pale  violet  bead,  appa- 
rently from  the  presence  of  Didymium. 

tjt  Insoluble  in  water.     Giving,  with  borax,  a  strongly-coloured  glass. 

WISERITE:  MnO,  CO2,  H2O.  In  yellowish  or  pale-red  fibrous 
coatings  on  certain  examples  of  Hausmannite  and  other  manganese 
ores. 

ZARATITE  (Texasite)  :  NiO,  CO2,  H2O.  In  thin  emerald-green 
coatings  on  nickle  ores.  Also  on  examples  of  Chromic  Iron  Ore  from 
Texas,  Penn. 

REMINGTONITE  :  CoO,  CO2,  H2O.  In  pinkish,  or  greyish-blue 
coatings  on  cobalt  ores.  ^ 

LINDAKERITE  (Calc-Uran  Carbonate).  In  coatings  and  crusts  on 
Pitchblende.  Yellowish-green.  Contains  (according  to  Lindaker) 
UO  37-03,  CaO  15-55,  CO2  24-18,  H'O  23-24.  YOGLITE  is  a  cupre- 
ous variety.  LIEBIGITE  is  also  a  closely  related  compound,  but  with 
45  p.  c.  aq.  All  occur  in  connection  with  pitchblende. 


NOTE  ON  TABLE  XIII. 

The  more  important  minerals  of  this  Table  comprise  :    (1)  Calcite,  Dolo- 
mite, Magnesite,  Siderite,   Rhodochrosite,  and  Smithsonite,  of  the  group  of 


140  BLOWPIPE    PRACTICE. 

Rhombohedral  Carbonates;  (2)  Aragonite,  Witherite,  Strontianite,  and  Cerus- 
site,  of  the  group  of  Prismatic  Carbonates ;  and  (3),  the  Cupreous  Carbonates, 
Malachite  and  Azurite. 

Calcite,  in  its  crystalization,  chiefly  affects  three  series  of  forms  :  (i)  Rhom- 
bohedrons, acute  and  obtuse  ;  (ii)  Scalenohedrons ;  and  (iii)  Hexagonal  Prisms, 
the  latter  commonly  terminated  by  the  three  planes  of  a  rhombohedron,  pen- 
tagonal in  shape  in  some  cases,  rhombohedral  in  others.  The  basal  plane,  when 
present,  is  usually  rough  or  dull.  Some  of  the  more  common  fhombohedrons 
comprise :  -  £ R  (polar  angle  135°) ;  -  2  R  (polar  angle  79°) ;  and  4  R  (p.  a.  66e). 
The  most  common  scalenohedron  has  the  following  interfacial  angles :  over 
long  polar  edge  159°24' ;  over  shorter  polar  edge  138°5' ;  over  middle  edge 
64°54'.  All  crystals  and  lamellar  examples  cleave  readily  into  a  rhombohedron 
of  about  105°5'  and  74C>55/,  but  these  angles  vary  to  within  about  30'  in  con- 
sequence of  isomorphous  replacements,  a  small  portion  of  the  lime  carbonate 
being  almost  constantly  replaced  by  carbonate  of  MgO,  FeO,  or  MnO.  Trans- 
parent examples  show  strong  double  refraction  in  the  direction  of  the  longer 
diagonal  of  a  rhombohedral  face.  Pseudomorphs,  after  Orthoclase,  Fluor  Spar, 
Barytine,  Celestine,  Gypsum,  Gaylussite,  &c.,  are  not  uncommon.  Calcite 
occurs  likewise  in  rock-masses,  forming  crystalline  limestone  (marble),  ordinary 
limestone,  oolitic  limestone,  chalk,  &c.,  and  in  various  stalactitic,  tufaceous, 
and  other  conditions.  Calcite,  after  simple  ignition  (without  the  aid  of  hydro- 
chloric acid,  although  it  is  always  advisable  to  add  a  drop  of  this),  shews  the 
red  and  green  calcium  lines  in  the  spectroscope  very  distinctly. 

Dolomite  much  resembles  calcite  in  its  general  characters  and  rhombohedral 
crystallization,  but  it  dissolves,  as  a  rule,  in  cold  acids  with  comparatively 
feeble  effervescence.  Both  hardness  and  sp.  gr.  are  also  slightly  higher.  The 
most  certain  method  of  distinction  is  the  determination  of  magnesia  in  the 
hydrochloric  acid  solution.  For  this  purpose  the  diluted  solution  is  first 
boiled  with  a  drop  or  two  of  nitric  acid,  and  ammonia  is  then  added  in  slight 
excess.  This  will  cause  a  slight  floceulent  precipitate  if  iron  be  present. 
Oxalate  of  ammonia  is  then  added  to  precipitate  the  lime  ;  this  is  filtered  off ; 
the  filtrate  tested  with  another  drop  of  oxalate  of  ammonia  to  make  sure  that 
all  the  lime  has  been  thrown  down,  and  the  magnesia  is  precipitated  by  some 
dissolved  phosphor- salt.  It  can  be  collected,  if  necessary,  and  ignited  with 
nitrate  of  cobalt  for  the  production  of  the  characteristic  flesh-red  tinge. 
Many  so-called  limestones  when  examined  in  this  manner  are  found  to  be 
"  dolomitic."  Ferruginous  varieties  of  Dolomite  pass  into  Ankerite. 

Magnesite  is  comparatively  rare  in  crystals,  but  occurs  commonly  in  more 
or  less  compact  or  granular  masses,  beds,  or  layers  of  a  white,  pale-grey  or 
yellowish  colour.  The  small  rhombohedrons  show  over  a  polar  edge  the  angle 
107°  16'  to  107°29'.  The  powder  by  ignition  with  a  drop  of  cobalt  solution,  is 
distinctly  reddened.  .The  absence  of  lime  can  be  proved  by  the  spectroscope  ; 
and  the  presence  of  magnesia  by  the  cobalt  test  or  by  precipitation,  as 
explained  under  Dolomite. 

Siderite  or  Spathic  Iron  Ore  occurs  under  various  conditions  :  crystallized 
in  metallic  veins,  &c.  ;  fibro-botryoidal ;  in  spherical  concretions  in  basaltic 


MINERAL   TABLES  : — XIII.  141 

rocks ;  pisolitic  in  Jurassic  and  other  strata  ;  massive  ;  and  lithoidal.  The 
crystals  are  usually  small  rhombohedrons  of  a  yellow  colour  (with  R :  R  107^ 
but  frequently  with  curved  faces),  also  acute  rhombohedrons  and  scalenohe- 
drons.  The  spheroidal  basaltic  variety  is  usually  dark-green  or  yellowish- 
brown,  with  radio-fibrous  structure.  The  pisolitic  variety,  dark-brown  or  grey, 
and  opaque  ;  and  the  lithoidal  and  massive  examples  dark-grey,  brown  or 
black,  and  also  opaque.  These  latter  kinds  commonly  occur  in  oval  or  nodular 
masses  in  coal  strata,  or  in  layers  mixed  with  coaly  matter.  Under  the  name 
of  Clay  Iron-Stone,  Black  Band,  &c.,  they  furnish  a  large  part  of  the  iron  of 
commerce,  but  are  always  very  impure  from  admixture  with  clay,  silica,  &c. 
They  are  also  more  or  less  altered,  as  a  rule,  into  brown  iron  ore.  The  nodules, 
when  split  open,  are  usually  found  to  contain  the  impression  of  a  fern-frond  or 
other  organic  body. 

Rhodochrosite  or  Manganese  carbonate  is  of  less  frequent  occurrence  than 
the  preceding  carbonates.  Its  crystals  are  mostly  small  rhombohedrons  (with 
usually  curved  faces)  sometimes  shewing  a  triangular  basal  plane  (R  :  R  106° 
51' — 107°) ;  but  it  occurs  commonly  in  botryoidal,  granular  or  lamellar  masses, 
of  a  pink  or  rose-red  colour,  with  dark-brown  altered  patches.  As  in  Magnesite 
and  Siderite,  it  effervesces  feebly  unless  the  acid  be  heated.  Its  red  colour  and 
intense  manganese  reaction,  BB,  with  carb.  soda,  generally  serve  to  distin- 
guish it  at  once  from  other  carbonates ;  but  many  examples  of  Magnesite, 
Siderite,  &c.,  give  a  more  or  less  strongly -marked  manganese  reaction.  No 
very  definite  lines  of  demarcation,  in  fact,  can  be  drawn  between  the  rhombo- 
hedral  carbonates  generally. 

Smithsonite,  or  zinc  carbonate,  occurs  mostly  in  aggregations  of  minute 
rhombohedrons,  or  in  botryoidal  or  incrusting  examples  of  a  white,  brownish, 
grey,  yellowish,  or  green  colour.  It  is  usually  more  or  less  vitreous  and 
transparent ;  but  is  sometimes  in  opaque,  grey  or  brown,  earthy  or  porous 
masses.  The  streak  is  white,  and  the  hardness  just  sufficient  to  scratch 
glass  ;  or  sufficient,  at  least,  to  scratch  fluor  spar  very  strongly.  In  powder, 
with  a  mixture  of  carb.  soda  and  borax,  it  yields  on  charcoal  a  sublimate  of 
ZnO, — bright-yellow  and  phosphorescent,  hot ;  white,  cold ;  and  light-green 
after  ignition  with  cobalt  solution. 

Aragonite — the  typical  representative  of  the  group  of  Prismatic  carbonates — 
is  identical  in  composition  with  the  rhombohedral  calcite.  It  occurs  frequently 
crystallized,  and  in  fibrous,  coralloidal,  and  other  masses.  The  crystals 
belong  to  the  Rhombic  System,  and  are  generally  six-sided  prisms,  composed 

of  four  V  planes  with  the  two  side  planes  of  a  brachy-prism  V,  terminated  by 
a  brachy-dome  P,  and  by  the  planes  of  a  rhombic  octahedron  P  ;  but  the  latter 

form  is  often  absent.  V  :  V  =  116°10'  j  V  :  V  =  121°55' ;  V  :  P  =  125°47'. 
Twins  and  compound  crystals  are  very  common.  Some  of  the  latter,  com- 
posed of  three  or  more  individual  crystals,  are  strikingly  pseudo-hexagonal  in 
character,  presenting  the  appearance  of  a  simple  six-sided  prism  with  large 
base.  The  colour  is  white,  yellow,  brownish-violet,  &c.  All  examples  dis- 


142  BLOWPIPE   PRACTICE. 

solve  with  strong  effervescence  in  cold  acids,  and  show,  after  moderate  ignition, 
the  characteristic  red  and  green  calcium  lines  in  the  spectroscope. 

Witherite,  carbonate  of  baryta,  also  presents  in  its  crystallization  a  pseudo- 
hexagonal  aspect.  The  crystals  are,  very  generally,  six-sided  pyramids,  but 
are  regarded  as  compound  crystals,  made  up  of  interpenetrating  rhombic- 
octahedrons.  Columnar,  botryoidal,  and  massive  examples  are  however  its 
principal  forms  of  occurrence.  Its  high  sp.  gr.  (over  4'0),  and  the  green  colour 
which  it  imparts  to  the  flame  border,  sufficiently  distinguish  it  from  other 
carbonates. 

Strontianite,  like  Witherite,  is  entirely  dissolved  by  fusion  with  carb.  soda ; 
and  its  sp.  gr.  is  comparatively  high  (3'6-3'8).  It  is  readily  distinguished, 
however,  by  the  intense  crimson  coloration  which  it  communicates  to  the 
flame-border,  and  by  the  characteristic  blue,  orange,  and  red  lines,  of  its 
spectrum.  Its  crystallization  is  identical  with  that  of  Arragonite,  and  is 
characterized  by  pseudo-hexagonal  combinations  and  twin  forms  ( V  :  V  — 

117°19' ;  V  :  V  =  12i°20'30"  ;  V:  2P  =  145°22').  Strontianite  occurs  more 
commonly,  however,  in  columnar,  fibrous,  granular  and  other  examples. 

Cerussite,  or  lead  carbonate,  is  also  identical  in  crystallization  with  Ara- 
gonite,  and  is  particularly  characterized  by  its  stellate  and  cruciform  groups 

(V:  V  =  117°14',  V:  2P  =  145°20').  The  lustre  is  strikingly  adamantine. 
This  character,  with  the  high  sp.  gr.  (6 '5)  of  the  species,  its  remarkable 
fragility,  and  its  blowpipe  reactions,  sufficiently  distinguish  it. 

The  copper  carbonates,  Malachite  and  Azurite,  yield  water  on  ignition,  and 
are  otherwise  distinguished  by  their  deep  green  and  blue  colours,  and  their 
copper  reactions.  Malachite  (although  often,  as  a  product  of  alteration,  entirely 
coating  octahedrons  and  dodecahedrons  of  red  copper  ore,  Cu2O)  is  very  rarely 
crystallized,  but  occurs  commonly  in  botryoidal,  fibrous  and  massive  examples, 
and  as  an  earthy  coating  on  copper  ores  generally.  Azurite,  the  blue  carbonate, 
is  frequently  in  groups  of  small  clino-rhombic  crystals,  more  or  less  indistinct 
in  form.  It  occurs  also  in  columnar  and  other  masses,  and  in  earthy  coatings 
on  copper  ores. 


[148] 


TABLE    XIV. 

[Aspect  non-metallic.     BB,  on  charcoal,  arsenical  fumes  or  odour.] 
A  —Entirely  volatilizable,  or  leaving  only  a  minute  residuum. 

(Streak  white). 

ARSENOLITE  (Arsenious  acid):  As  75-8,  O  24-2.  Reg.;  H  1-2; 
G  3'7 ;  in  white,  crystalline  or  acicular  groups  and  coatings,  and  in 
earthy  crusts.  CLAUDETITE  (Dana)  is  a  rhombic  species,  in  small 
sub-pearly  laminae.  G  3 -85. 

(Streak  black). 

NATIVE  ARSENIC,  weathered  examples.  In  dull,  black,  earthy 
masses,  often  coating  the  metallic-grey  or  tin-white  unaltered  metal. 
See  TABLE  I. 

B  —Yielding,  BB,  metallic  globules  on  charcoal,    (A  mixture 
of  carb-  soda  and  borax  assists  the  reaction). 

(BB,  a  silver  globule). 

PROUSTITE  (Light-red  Silver  Ore).  Ag  65 '46,  As  15-15,  S  19-39. 
Henri-Hex. ;  H  2-2-5  ;  G  5*4-5-6  ;  red,  more  or  less  translucent,  with 
adamantine  lustre ;  streak,  red. 

XANTHOCONE  :  Ag  64-08,  As  14-83,  S  21-09.  Hemi-Hex.,  mostly 
tabular.  H  2-2-5 ;  G  5-0-5-2.  Orange  or  brownish-yellow,  trans- 
lucent or  transparent,  with  adamantine  lustre.  Streak  orange-yellow. 

RITTINGERITE  :  Normally  AgAs  (with  57*7  Ag),  but  S  commonly 
present.  Clino-Rh. ;  H  2-5-3 ;  G  5-6-3.  Iron-black,  red  by  trans- 
mitted light ;  streak  orange-yellow.  Lustre  in  general  strongly  sub- 
metallic.  See  TABLE  IX. 

POLYBASITE,  arsenical  varieties.  Ag  (64-74),  Sb,  As,  S ;  !Rh. ; 
H  2'5;  G  6-0-6-2.  Iron-black,  red  in  thin  pieces  by  transmitted 
light;  streak,  commonly  dark-red.  Lustre,  usually  metallic.  See 
TABLE  IV. 

All  the  above  arsenical  silver  ores  fuse  per  ne  in  the  flame  of  a  candle,  with- 
out the  aid  of  the  blowpipe.  Rittingerite  and  Polybasite  are  still  imperfectly 
known. 

(Cu  reaction). 

OLIVENITE:  CuO  56-15,  As'O6  40-66,  H'O  3-19.  Kb,  (V:T 
92°30') ;  H  3 ;  G  4-3-4-6  ;  dark-green,  brownish \  streak,  paler. 


144  BLOWPIPE   PRACTICE. 

EUCHROITE:  CuO  47-15,  As205  34-15,  H20  18-70.  Rh.  (V :  V 
117°20');  H  3-4;  G  3-3-3-5;  emerald-green,  leek-green;  streak, 
paler.  CHLOROTILE  is  closely  related. 

ERINITE  :  CuO  60,  As2O5  34-6,  H2O  5'4.  Mostly  in  concentric- 
lamellar  examples ;  H  4-5;  G4-0;  emerald-green;  streak,  paler. 

TIROLITE  (Kupferschaum)  :  CuO  50-32,  As206  29-15,  H2O  20-53. 
Mostly  in  radio-fibrous  mammillary  examples.  H  1-2  ;  G  3-1.  Green 
or  greenish-blue ;  streak,  paler.  Most  examples  are  intimately  mixed 
with  CaO,  CO2.  The  presence  of  Ca,  readily  shewn  by  spectroscope. 

CLINOCLASE  (Abichite,  Aphanese,  Strahlerz) :  CuO  62-65,  As205 
30-25,  H2O  7-10.  Clino-Rh.;  H  2«5-3;  G  4-2-4-4;  dark-green, 
bluish-green,  blackish  externally  ;  streak,  paler. 

LIROKONITE  (Linsenerz) :  CuO,  As2O5,  A12O3,  H20  (25  per  cent.). 
Clino-Rh.;  H2-2'5;  G  2 -8-2 -95;  light-blue,  sometimes  green;  streak, 
paler. 

CHALCOPHYLLITE  (Copper  Mica) :  CuO,  As205,  A12O8,  H20  (23-32 
per  cent.).  Hemi-Hex.,  tabular,  micaceous.  H  2 ;  G  2-5 ;  bright 
emerald-green ;  streak,  paler. 

ZEUNERITE:  CuO  7'71,  TPO»  55-95,  H20  14.  Tet.,  isomorphous 
•with  Chalcolite  or  Torbernite.  H  3*5  ;  G  5*76;  orange  or  wax-yellow, 
with  adamantine  lustre ;  streak,  paler. 

ADAMITE  :  Cupreous  varieties.  Green.  G  4*35 ;  zinc  sublimate 
with  carb.  soda  on  charcoal.  See  below. 

(Pb  reaction). 

MIMETESITE  :  PbO,  As2O5  90-7  ;  PbCl2  9-3.  Hex.  (crystals  often 
sub-spherical).  H  3-5-4 ;  G  7-7*3  ;  yellow,  green,  greyish,  colourless, 
with  resino-adamantine  lustre.  KAMPYLITE  and  HEDYPHANE  (G  5-5) 
are  more  or  less  calcareous  and  also  phosphatic  varieties.  Some  of 
the  orange-yellow  examples  contain  lead  chromate.  All  give  Cl 
reaction  with  phosphor-salt  and  CuO. 

AR^JOXENE:  PbO,  ZnO,  V206,  As2O5.  Radio-fibrous;  H  3; 
G  5  -8  ;  brownish-red ;  streak,  yellow. 

CARMINITE  (Karminspath) :  PbO  23-62,  Fe208  29-14,  As206  47'24. 
Acicular,  mammillated.  H  2-5  ;  G  4'1 ;  red;  streak,  reddish-yellow. 

BEUDANTITE  :  PbO,  Fe203,  P2O5,  As2O5,  SO3,  H2O.  Hemi-Hex.  (?) 
H  3'5  ;  G  4:0.  Olive-green;  streak,  yellowish.  A  doubtful  species. 


MINERAL   TABLES  : — Xltf.  1 45 

(.Bi  reaction). 

RHAOITE  :  Bi2O*  79  5,  As2O5  15-6,  H2O  4-9,  Mostly  botryoidal  or 
in  small  spherical  examples.  H  45-5  ;  G-  6*82  j  light-green ;  streak, 
very  pale  green  or  white.  In  bulb-tube  crumbles  into  yellow  powder. 
Accompanies  uran  ores  at  Schneeberg. 

WALPURGINITB  :  Bi2O8,  IPO3,  As2O5,  H20  (4-5).  Clino-Rh.?; 
orange  or  wax  yellow,  with  resino-adamantine  lustre ;  streak,  paler ; 
H3-5;  G  5-76.  Accompanies  uran  ores  at  Schneeberg.  ATELESITE 
is  apparently  related. 

C.— No  metallic  globules,  BB,  on  charcoal. 

(Zn  reaction.     Characteristic  sublimate  with  carb.  soda  on  charcoal). 

ADAMITE  :  ZnO  56-6,  As205  40-2,  H'O  3-2,  but  some  green  examples 
contain  CuO,  and  red  examples,  CoO.  Rh. ;  H  3-5 ;  G  4-3-4-35. 
Normally,  yellow ;  but  often  violet,  red,  or  green  ;  streak,  paler. 

KOTTIGITE  :  Zinc-holding  var.  of  ERYTHRINE.     See  below. 

(Co  reaction). 

ERYTHRINE  (Cobalt  Bloom)  :  CoO  37-56,  AsW  38-40,  H20  24-04. 
Clino-Rh. ;  H  2-5;  G  2-9-3-0.  Red,  purplish-red;  streak,  paler. 
Some  earthy  varieties  contain  intermixed  arsenolite.  KOTTIGITE  is 
a  zinc-holding  var. 

ROSELITE  :  CaO,  MgO,  CoO,  As2O5,  IPO  (8-20).  Rh.  or  Cl.-Rh. 
H  3-3-5  ;  G  3-46  ;  deep  rose-red  ;  pale-reddish  or  white  streak.  The 
presence  of  Ca  easily  shewn  by  the  spectroscope. 

CABRERITE  :  A  cobaltiferous  var.  of  ANNABERGITE.     See  below. 

(Ni  reaction). 

ANNABERGITE  (Nickel  Green):  NiO  37-25,  As203  38-59,  H2O 
24-16.  Acicular,  efflorescent;  H  1-2*5;  G  3;  apple-green,  greenish - 
white.  CABRERITE  is  a  variety  containing  CoO  and  MgO.  Green 
and  yellowish  anhydrous  nickel  arseniates  have  also  been  recognized 
(G  4-9). 

(Fe  reaction,  BB,  magnetic  slag  or  bead). 

PHARMACOSIDERITE  (Cube  Ore):     Fe2O3  40,  AsW  43-13,  H'O 
16-87.     Reg.     (See  Note  at  end  of  TABLE).     H  2-5  ;  G  2-9-3  ;  dark- 
green,  yellow,   brownish,;  streak,   paler.     Mostly  in  minute   cubes 
tetrahedrally  moc&fied. 
11 


BLOWPIPE    PRACTICE. 

SCORODITE :  Fe'O*  34-63,  As2O5  49-78,  H2O  15-59.  Rh. ;  H  3-5-4; 
G  3-1-3-3  ;  dark-green,  brownish,  indigo-blue ;  streak,  paler. 

ARSENIOSIDERITE  :  Fe2O3  39-4,  CaO  13-8,  As205  37-9,  H20  °>-9. 
Fibrous-botryoidal.  H  1-2 ;  G  3-9 ;  brownish-yellow,  with  silky 
lustre. 

SYMPLESITE  :  FeO,  Fe203,  As'O6,  IPO  (25-28  per  cent.).  Clino- 
Rh.,  acicular ;  H  2-5  ;  G  2-9-3-0  ;  pale  blue,  green,  with  pearly  lustre. 

PITTIZITE  :  Fe2O*,  As2O6,  SO3,  H2O  (12-29  per  cent.).  Amorphous, 
stalactitic.  H  2-5-3;  Gr  2-3-2-5;  brownish-yellow,  dark-brown; 
streak,  paler. 

CARMINITE  ;  BEUDANTITE  :  Contain  PbO.     See  above. 

(MnO  reaction). 

CHONDRO-ARSENITE  :  MnO,  MgO,  CaO,  As2O9,  H2O  (7-8  per  cent.). 
In  small  granular  concretions  of  a  wax  yellow  colour.  H  3'0. 

Bfi RZ ELITE  :  Gives  Mn  reaction  in  most  examples;  Ca-lines  in 
spectroscope ;  no  water.  See  below. 

DURANGITE  :  Strong  Na  and  F  reactions.     Orange-red.    See  below. 

( U*0*  reaction). 

TROEGERITE:  IPO3  65-95,  As206  17-55,  H20  16-50.  Clino-Rh., 
tabular;  H  2-2'5 ;  G  3-23-3-27;  lemon  yellow;  streak,  yellowish- 
white.  Easily  fusible. 

URANOSPINNITE  :  U2O8  59-18,  CaO  5-47,  As20s  19-37,  IPO  16-19. 
Tetr.  1  scaly  or  thin  tabular;  H  2-2*5  ;  G  3-45  ;  yellowish-green. 

(MgO  and  CaO  reactions.     Ca-lines  well  shewn  in  spectroscope). 

BERZELITE  (KUHNITE)  :  CaO,  MgO,  MnO,  As2O5.  Massive ;  H  5 
(or  4-5);  G  2-5-2-55;  yellow,  yellowish-white.  Nearly  infusible. 
No  water  evolved  in  bulb-tube. 

PHAKMACOLITE  ;  CaO  24-90,  As2O5  51-10,  IPO  24.  dino-Eh., 
but  mostly  acicular,  fibrous,  earthy,  &c. ;  H  1-5-2-5 ;  G  2*73. 
Normally  colourless  or  white.  Easily  fusible. 

HAIDINGERITE:  CaO  28-81,  As2O6 56-87,  IPO  14-32.  Rh.;  G  2-9; 
otherwise  like  Pharmacolite,  but  of  rare  occurrence. 

WAPPLERITE:  CaO,  MgO,  As2OB,  IPO  (18-20  per  cent.).  Clino- 
R,h. ;  H  1-5-2-5;  G  2-5;  colourless  or  white.  Very  easily  fusible. 
HOERNESITE  is  a  related,  but  purely  magnesian,  arseniate  (with 
IPO  29  per  cent.),  recognized  by  Kengott  in  the  kaiserlichen  min. 
Cabinet  of  Vienna. 


MINERAL  TABLES: — xiv.  147 

(Na  reaction). 

DURANGITE  (J.  G.  Brush) :  Na2O,  Li2O,  APO3,  Fe*O,  MnO, 
As'O5,  F.  Clino-Rh.;  H  5;  G  3-94-4-07;  orange-red.  Easily 
fusible.  With  sulphuric  acid,  fluorine  reaction.  Hitherto,  only- 
recognized  as  accompanying  tin  ore  and  colourless  topaz  in  the  Pro- 
vince of  Durango,  Mexico. 


NOTE  ON  TABLE  XIV. 

This  Table  is  composed  essentially  of  arseniates.  The  exceptions  comprise 
&  few  silver  sulpharsenites  in  which  the  lustre  is  mostly  non-metallic,  and  the 
naturally  occurring  arsenious  acid  or  anhydride  As203.  The  only  minerals  of 
thfc  Table  likely  to  come  under  ordinary  observation,  include  :  (1)  The  "  Light- 
K 3d  Silver  Ore,"  Proustite  ;  (2)  The  Cupreous  Arseniatea — Olivine,  Clinoclase, 
Liroconite,  Ohalcophyllite  and  Tirolite ;  (3)  The  Cobaltic  Arseniate,  Erythrine; 
(4)  The  Ferruginous  Species,  Pharmacosiderite  and  Scorodite  ;  (5)  The  Lime 
Arseniate,  Pharmacolite  ;  and  (6)  the  Lead  Chloro- Arseniate,  Mimetesite. 

Proustite  or  light-red  silver  ore,  the  arsenical  silver  blende  of  some  nomen- 
clatures, is  readily  recognized  by  its  deep  or  bright  red  colour,  red  streak  and 
adamantine  lustre  ;  as  well  as  by  the  large  silver-globule  obtained  from  it  by 
the  blowpipe.  It  frequently  accompanies  Native  Arsenic.  It  occurs  both 
crystallized  and  massive.  The  crystals  are  generally  small,  and  are  not  always 
readily  made  out  in  consequence  of  distortion  by  irregularity  in  the  size  of 
corresponding  planes.  Commonly,  they  consist  of  hexagonal  prisms  terminated 
by  a  rhombohedron  (with  R  :  K  =  107°50'},  or  of  scalenohedrons.  Small 
fragments  melt  in  the  candle  flame,  without  the  aid  of  the  blowpipe.  Boiled 
with  caustic  potash,  the  powder  becomes  immediately  black,  and  As2S3  is 
dissolved.  This  is  thrown  down,  as  a  yellow  flocculent  precipitate,  by  a  drop 
or  two  of  hydrochloric  acid. 

The  copper  arseniates  are  green,  or  more  rarely  blue,  in  colour,  and,  as  a 
rule,  they  detonate  or  deflagrate  somewhat  strongly  when  ignited  on  charcoal. 
Olivine  and  Clinoclase  are  usually  dark-green  or  blackish-green  (though  some- 
times brown  or  brown-yellow),  and  both  occur  frequently  in  small  crystals, 
and  in  radiated- fibrous,  reniform,  and  other  uncrystallized  examples.  The 
Olivine  crystals  are  rhombic,  and  the  Clinoclase  crystals  clino-rhombic  com- 
binations. Clinoclase  is  almost  constantly  in  radiated  groupings,  whence  its 
old  German  name  of  Strahlerz.  Olivine  yields  only  3*20  per  cent.  aq. 
Clinoclase  7  per  cent.  Liroconite  is  very  usually  of  a  light-blue  colour,  though 
sometimes  green.  It  occurs  mostly  in  very  small  clino-rhombic  crystals  which 
present  in  general  an  ortho-rhombic  aspect,  and  sometimes  resemble  slightly 
distorted  octahedrons.  In  the  bulb-tube  it  yields  (without  decrepitation)  a 
large  quantity  of  water  (25-26  per  cent.).  Chalcophyllite  is  rarely  in  distinct 
crystals,  but  generally  in  micaceous  or  thin  tabular  examples  of  a  bright 


148  BLOWPIPE    PRACTICE. 

emerald-green  colour,  with  metallic-pearly  lustre  on  the  broad  surfaces  of  the 
laminae.  In  the  bulb-tube  it  decrepitates  strongly  and  yields  a  large  amount 
of  water  (23-32  per  cent,).  Tirolite  or  Tyrolite  is  unknown  in  crystals.  Most 
commonly  it  occurs  in  bright  green  or  blue  radiated  examples,  or  in  reniform 
or  fine  scaly  masses.  Thin  foliae  are  flexible.  The  specimens  hitherto  examined 
contain  13-14  per  cent,  carbonate  of  lime,  either  in  combination  or  as  an 
intermixture.  The  presence  of  Ca  is  readily  shewn  by  the  spectroscope^ 
especially  if  the  copper  be  first  reduced  by  fusion  with  carb.  soda  on  charcoal, 
and  the  resulting  slag  be  moistened  with  a  drop  or  two  of  hydrochloric  acid. 
The  amount  of  water  equals  20-21  per  cent. 

Erythrine,  the  cobaltic  arseniate,  is  especially  distinguished  by  its  peach- 
blossom  red  colour,  and  by  the  deep-blue  glass  which  it  forms  by  fusion  with 
borax.  »  It  occurs  in  small  clino-rhombic  crystals,  but  more  commonly  in 
bladed,  acicular  and  efflorescent  examples.  The  thin  folise  are  flexible. 
Easily  fusible.  Water,  24  per  cent. 

The  ferruginous  arseniates,  Pharmacosiderite  and  Scorodite,  distinguished 
from  the  cupreous  and  other  arseniates  by  the  magnetic  slag  which  they  yield, 
BB,  on  charcoal,  are  distinguished  individually  by  their  crystallization. 
Pharmacosiderite  is  almost  always  in  very  minute  cubes,  truncated  on  alternate 
angles  by  the  triangular  planes  of  the  tetrahedron.  Its  colour  is  dark-green, 
passing  into  brownish-yellow  and  brown,  and  the  little  crystals  are  usually  in 
drusy  aggregations.  Scorodite  when  crystallized  is  commonly  in  small  prisms 
terminated  by  an  acute  rhombic  pyramid,  but  it  occurs  also  frequently  in 
fibrous  and  other  examples.  The  colour  is  dark-green  or  indigo-blue,  inclining 
to  reddish-brown  in  some  specimens.  The  hardness  exceeds  that  of  calcite, 
whilst  Pharmacosiderite  is  slightly  under  calcite  in  hardness. 

Pharmacolite,  the  ordinary  lime  arseniate,  is  comparatively  unimportant. 
It  occurs  mostly  as  a  white  efflorescence,  or  in  acicular  crystals,  on  arsenical 
cobalt  and  iron  ores. 

Mimetesite,  chloro- arseniate  of  lead,  is  readily  distinguished  from  other 
minerals  of  the  Table  by  its  high  sp.  gr.  (7 '0-7 '3),  as  well  as  by  the  lead 
globule  which  it  yields,  BB,  on  charcoal.  It  belongs  by  its  crystallization 
and  chemical  formula  to  the  Apatite  group,  and  often  passes  into  Pyromorphite, 
the  corresponding  lead  phosphate.  The  crystals,  hexagonal  prisms,  or  com- 
binations of  prism  and  pyramid,  are  very  commonly  curved  into  almost 
globular  shapes.  The  colour  is  generally  yellow,  more  rarely  grey,  brown,  or 
green,  with  resino-adamantine  lustre.  Fused  in  the  platinum  forceps,  the 
bead  crystallizes  on  cooling,  but  on  charcoal  it  becomes  reduced. 


[U9] 

TABLE    XV. 

[Lustre  non-metallic.     BB,  on  charcoal,  antimonial  fumes  and  deposit.] 

A  —On  charcoal,  reducible  to  metallic  antimony  and  rapidly 

volatilized. 

(S  reaction  with  carb.  soda). 

KERMESITE  (Pyrostibite,  Red  Antimony  Ore,  Antimony  Blende). 
Sb2S*  70,  Sb2O3  30.  Red,  bluish  or  brownish  red,  with  red  streak 
and  adamantine  lustre.  Rh.  (or  Clino  Rh.  *? ),  but  mostly  acicular  or 
fibrous;  H  1-1 '5;  G  4-5  4-6.  Fusible  in  candle-flame. 

(No  8  reaction). 

VALENTINITE  :  Sb  83-56,  0  16-44.  Rh.,  mostly  tabular  or  acicular. 
H  2-3;  G  5'3-5'6;  normally  white,  but  sometimes  pale  reddish  or 
brownish  from  admixtures.  Becomes  yellow  on  ignition,  and  melts 
very  easily.  In  the  bulb-tube,  sublimes  entirely,  if  pure.  SENAR- 
MONTITE  has  the  same  composition  (Sb2O3)  and  general  characters, 
but  is  Regular  in  crystallization.  The  crystals  are  commonly  octahe- 
drons, often  with  curved  planes. 

CERVANTITE :  Sb2O3  47-40,  Sb206  52-60.  Rh.1  acicular,  encrusting ; 
H  3-0-4-0  (or  5  ? ) ;  G  4'08.  Yellow,  yellowish-white.  Infusible, 
but  reducible  on  charcoal.  Not  volatile  in  the  bulb-tube. 

(No  S  reaction  ;  aq  in  bulb-tube). 

ANTIMONY  OCHRE  :  Sb203,  mixed  more  or  less  with  Sb205,  and 
yielding  H2O  on  ignition.  Earthy,  encrusting ;  G  3'8 ;  yellow,  yel- 
lowish-white. Reduced  and  volatilized  on  charcoal. 

STIBLITE:  Sb203,  Sb2O5,  H20  (5-6  per  cent.).  Compact,  pseudo- 
morphous  after  antimony  glance.  Yellow,  yellowish-white.  Reduced 
and  volatilized  on  charcoal,  the  reduction  (as  in  all  compounds  of 
Sb203  -f  Sb'O5)  assisted  by  addition  of  carb.  soda. 

B.— On  charcoal  partially  vol ,  a  metallic  globule  remaining. 

(Ag  reaction), 

PYROSTILPNITE  (Fire  Blende  in  part):  Ag  (62  per  cent.)  Sb,  S. 
Clino-Rh.  1  tabular,  foliated.  H  2 ;  G  4*2-4-3 ;  orange-yellow, 
brownish-red  ;  streak,  red  or  yellow ;  lustre  pearly-adamantine.  BB, 
antimonial  fumes  and  large  silver-globule. 


150  BLOWPIPE    PRACTICE. 

PYRARGYRITE  ;  POLYBASITE  :  Ag,  Sb,  S.  Iron-black,  or  deep-red  in 
thin  pieces  by  transmitted  light.  Streak,  red.  Lustre  essentially 
metallic  or  sub-metallic.  See  TABLES  IV.  and  IX. 

(Cu  reaction}. 

RIVOTITE  :  CuO,  Sb2O5,  mixed  with  carb.  lime,  &c.  A  doubtful 
species.  Compact j  yellowish-green;  H  3'5-4'Oj  G  3*55-3-62 
(Ducloux). 

(Pb  reaction). 

BINDHEIMITE  (Bleiniere) :  PbO,  Sb205,  H2O  (6  per  cent.).  A 
doubtful  compound.  Massive,  earthy,  &c. ;  H  l-4j  G  3'9-4'7. 
Greyish-white,  yellowish,  brownish,  green,  &c.  Often  veined  or 
clouded  in  different  tints. 

N ADORITE  :  PbO,  Sb2O3  -f-  PbCP.  Rh. ,  tabular.  H  3  -0 ;  G  7  -02 ; 
yellowish  or  greyish-brown.  Hitherto  found  only  in  .calamine 
deposits  in  Algeria. 

C.— On  charcoal  partially  vol ,  an  earthy  mass  remaining. 

ROMEITE:  CaO  19-5,  Sb  63-8,  O  16'7.  In  groups  of  small  tetra- 
gonal octahedrons  of  a  yellow  or  reddish  colour.  H  5 -5  (?),  G  4 '67- 
4*71.  The  presence  of  Ca  in  the  residuum,  left  on  charcoal  after 
roasting,  is  easily  recognized  by  the  spectroscope.  Part  of  the  CaO 
is  commonly  replaced  by  MnO  and  FeO. 


NOTE  ON  TABLE  XV. 

The  minerals  of  this  Table  consist  chiefly  of  rare  or  obscurely  known  examples 
of  antimouial  oxidea,  alone,  or  combined  with  lead  oxide,  &o.  None  of  these 
compounds  are  of  mineralogical  importance.  The  only  species  of  ordinary 
occurrence  referred  to  in  the  Table  is  the  mineral  Kermesite  or  Pyrostibite, 
a  compound  of  2Sb2S3  with  Sb203.  This  occurs  commonly  in  association  with 
Antimony  Glance,  It  is  usually  in  radiating- fibrous  or  tufted  plumose  masses 
of  a  deep  bluish-red  or  brownish-red  colour,  with  red  streak  and  adamantine 
(more  or  less  sub-metallic)  lustre.  In  caustic  potash,  the  powder  assumes  a 
yellow  colour,  and  on  boiling  is  rapidly  dissolved.  Fusible  and  volatilizable 
in  the  caudle-flame  without  the  aid  of  the  blowpipe. 


[151] 

TABLE    XVI. 

[Lustre  non-metallic.     BB,  with  carb.  soda  strong  sulphur-reaction.] 

A  —Anhydrous  species.    No  water  (or  traces  only) 
in  bulb-tube. 

A*.—  REDUCIBLE  TO  METAL  PER  SE  OR  WITH  CARB.  SODA. 
(BB,  a  lead  globule). 

ANGLESITE  :  PbO  73-6,  SO3  26-4.  Rh.  (V :  Y  103°44') ;  H  3 
(or  sometimes  slightly  lower) ;  G  6-1-6-4  (commonly  6-3) ;  colourless, 
grey,  yellowish,  &c. ;  streak,  white.  Sol.  in  caustic,  potash.  SAR- 
MANITE  is  a  supposed  clino-rhombic  species  of  similar  composition. 

LANARKITE  :  PbO,  SO3  57-6  -f'PbO  424.  Clino-Rh. ;  H  2*0-2-5; 
G  6 -5-6 -9 ;  pale  greenish-white,  yellowish,  grey.  Flexible  in  thin 
pieces.  By  alteration,  partially  converted  into  carbonate,  and  then 
effervesces  in  acids. 

LEADHILLITE  :  PbO,  CO2  -|-  PbO,  SO ;  effervesces  in  acids.  See 
TABLE  XIII. 

(Pb  and  Cu  reactions.     Flame  coloured  strongly  green.      With  carb.  soda,  lead 

sublimate.      With  boracic  acid,  copper  globule). 

CALEDONITE  ;  PbO,  CuO,  SO3  (CO2  and  H2O  by  alteration  ?)  Rh. 
(or  Clino-Rh.  ?)  V  :  V  95°.  Light  bluish-green ;  streak,  greenish- 
white;  H  2-5-3;  G  6 -4.  Generally  effervesces  in  acids. 

A2.— NOT  REDUCIBLE  TO  METAL,  BB.  ATTACKED  OR  DISSOLVED  IN  POWDER  BY 
HOT  HYDROCHLORIC  ACID,  WITH  EMISSION  OF  H2S  ODOUR. 

(  With  carb.  soda,  zinc  sublimate  on  charcoal). 

SPHALERITE  or  ZINC  BLENDE  :  Zn  67,  S  33.  Reg.  (mostly  inclined 
hemihedral);  H  3*5-4;  G  3-9-4-2.  Brown,  black  (often  red  by 
transmitted  light),  green,  yellow,  rarely  colourless;  streak,  mostly 
pale-brown.  Many  yellow  examples  are  phosphorescent  by  surface- 
abrasion.  Practically  infusible.  The  lustre  varies  from  adamantine 
to  sub-metallic  and  metallic  proper.  See  TABLES  III.  and  X.  MAR- 
MATITE  and  CHRISTOPHITE  are  dark,  ferruginous  varieties. 

VOLTZINE:  ZnS  82-7,  ZnO  17-3.  H  3-5-4-0;  G  3-5-3-8.  Brownish- 
red,  yellow,  greenish ;  streak,  pale-brown.  Practically  infusible. 

( With  carb.  soda,  red-brown  cadmium-sublimate). 

GREENOCKITJE  :  Ca  77-8,  S  22-2.  Hex.,  hemimorphic  (crystals 
mostly  small  acute  pyramids,  with  lower  half  entirely  replaced  by; 


152  BLOWPIPE    PRACTICE. 

basal  plane).  H  3-3-5  ;  G  4-8-4-9.  Yellow,  orange,  brownish,'  with 
yellow  streak  and  adamantine  lustre.  Infusible.  On  ignition, 
becomes  deep-red  whilst  hot,  but  generally  decrepitates. 

( With  carb.  soda,  strong  manganese  reaction}. 

ALABANDINE:  Mn  63-2,  S  36*8.  Black,  brownish-black,  with 
greenish  streak,  and,  in  general,  sub-metallic  aspect.  No  sublimate 
in  closed  tube.  See  TABLE  X. 

HAUERITE  :  Mn  46-22,  S  53-78  (  =  MnS2).  Reg.,  parallel-hemi- 
hedral,  and  thus  resembling  Iron  Pyrites  in  crystallization.  Dark 
red-brown,  brownish-black,  with  brownish-red  streak,  and,  in  general, 
sub-metallic  lustre.  In  closed  tube,  turns  green,  and  gives  sublimate 
of  sulphur.  See  TABLE  X. 

A*.— NOT  REDUCIBLE  TO  METAL.    NO  ODOUR  OF  H*S  EVOLVED  BY   TREATMENT 
WITH   HYDROCHLORIC  ACID.*     TASTELESS,   INSOLUBLE. 

f  Entirely  diss  )lved,  BB,  by  carb.  soda. 
(Flame,  coloured  apple-green). 

BARYTINE  (HEAVY  SPAR)  :  BaO  65-7,  SO3  34-3,  a  portion  of  the 
BaO  sometimes  replaced  by  SrO  or  CaO.  Rh.  (V  :  V  101°40'). 
H  3'5  ;  G  4-3-4-7  ;  colourless,  white,  yellow,  flesh-red,  brown,  &c., 
with  white  streak.  BB,  generally  decrepitates.  Fusible  into  a 
white  caustic  enamel,  the  flame  coloured  pale-green.  BARYTO- 
CELESTINE  (G  4-24)  is  a  mixture  or  isomorphous  union  of  BaO, 
SO3  and  SrO,  SO3.  BARYTO-CALCITE  (G  4-0-4-3)  =  BaO,  SO3  + 
CaO,  SO3.  As  regards  the  latter,  see  below. 
(Flame  coloured  crimson). 

CELESTINE:  SrO  56-52,  S0»  43-48.  Rh.  (V  :  V  103°40'-  104°10'); 
H  3-3-5;  G  3-9-4-0;  colourless,  pale-blue,  indigo-blue,  yellowish,  &c., 
with  white  streak.  BB,  generally  decrepitates.  Fuses  into  a  white 
caustic  enamel,  and  imparts  a  crimson  coloration  to  the  flame. 

ft  In  part,  only,  dissolved,  BB,  by  carb.  sr,da. 
ANHYDRITE:  GaO  41 -18,  SO*  58-82.  Rh.  (Y  :  Y  100°30') :  H 
3-3-5 ;  G  2-8-3.  Mostly  in  colourless,  white,  bluish,  or  reddish 
lamellar  masses,  with  pearly  lustre  on  cleavage  planes ;  streak, 
white.  BB,  fusible  into  a  white  caustic  enamel.  Colours  the  flame- 
border  red,  after  prolonged  exposure, 

*  The  presence  of  Ba,  Sr,  and  Ca,  in  minerals  of  this  section,  is,  readily  determined  by  the 
spectroscope.  See.  Outline  of  Blowpipe  Practice,  page  55. 


MINERAL   TABLES  : — XVI.  153 

BARYTO-CALCITE  :  A  compound  of  the  sulphates  of  baryta  and 
lime.  Properly,  a  calcareous  var.  of  Heavy  Spar,  but  referred  to 
here  as  being  only  partially  soluble,  BB,  in  carb.  soda,  the  lime 
remaining  unattacked.  G  4-0-4-3.  Imparts  a  pale-green  tint  to  the 
flame-border ;  but  the  orange-red  Ca-line  comes  out  prominently  in 
the  spectroscope. 

A*.— SOLUBLE.     SALT  OB  BITTER  TO  THE  TASTE. 

(Ammonia  reaction.     BB,  entirely  vol.) 

MASCAGNINE  :  Am  39-4,  SOS  60-6.  Rh.  (V  :  V  121°8'),  but  chiefly 
in  white  or  yellowish  crusts  or  mammillated  masses  on  certain  lavas. 
H  2-2-5  ;  G  1-7-1-8.  Taste,  sharp  and  bitter. 

(Flame  coloured  violet.  Red  X-line  well  defined  in  spectroscope). 
GLASERITE  (ARCANITE)  :  K'O  54,  SO3  46.  Rh.  (V  :  V  120°24> 
but  mostly  in  white  earthy  crusts.  H  2-5  ;  G  2*7.  Taste,  bitter. 
BB,  generally  decrepitates,  melts  easily,  and  crystallizes  over  the 
surface  on  cooling.  APTHALOSE  is  a  rhombohedral  potash  sulphate 
from  Vesuvius. 

(Flame  coloured  intensely  yellow.     Na-line,  only,  in  spectroscope). 
THENARDITE:  Na2O  43-66,  SO3  56-34.     Rh.,  but  mostly  in  drusy 
or  earthy  crusts  and  coatings  of  a  white  or  greyish  colour;  H  2*5  ; 
G  2*67.     Taste,  saltish,  alkaline.     Easily  fusible,  and  on  charcoal 
reduced  to  sulphide,  and  absorbed. 

(In  spectroscope,  green  and  orange-red  Ca-lines,  and  yellow  Na-line). 
GLAUBERITE:  Na2O,  SO3  51,  CaO,  SO5  49.  Clino-Rh.;  H  2-5-3-0; 
G  2-7-2-8.  Taste,  saltish  and  bitter.  White,  grey,  yellowish,  red, 
<kc.  Somewhat  deliquescent.  BB,  decrepitates,  fuses  easily,  and 
becomes  reduced  to  sulphide.  In  carb.  soda,  the  lime  remains  undis- 
solved.  In  water,  only  partially  soluble. 

B.— Hydrous  compounds.    Yielding  water  by  ignition  in 
bulb-tube 

Bi.— FORMING,  BB,  WITH  BORAX  A  PRACTICALLY  UNCOLOURED  BEAD. 

f  Readily  soluble  in  water,  and  possessing  a  bitter  or  other  taste. 

(On  charcoal,  BB,  entirely  absorbed.     Flame  coloured  intensely  yellow). 
MIRABIUTE  (GLAUBER'S  SALT)  :  Na'O  19-3,  SO3  24-8,  H2O  55-9. 
Clino-Rh.,  but  mostly  efflorescent,  &c. ;  H  1-2;  G  1'4- 1  -5.     Taste, 
cooling  and  bitter. 


154 


BLOWPIPE   PRACTICE. 


(The  residuum,  left  BE  on  charcoal,  assumes  by  ignition  with  cobalt  solution  a 
Jme,  blue  colour). 

ALUM  (Potash  Alum,  Kalinite) :  K2O  9-95,  APO3  10-82,  SO3  33-75, 
H20  4:5-48.  Reg.,  octahedral,  but  commonly  in  white  or  greyish 
crusts,  <fec.  H  (crystals)  2-2-5 ;  G  1  -7-1  -9.  Red  K-line  in  spectroscope. 

SODA-ALUM  :  Na2O,  APO,  SO3,  H2O.  In  white  or  greyish  crusts, 
&c.  BB,  strong  yellow  flame,  and  yellow  Na-line  in  spectroscope. 

AMMONIA  ALUM  (Tschermigite)  :  Am,  APO8,  SO3,  H2O.  Earthy 
crusts.  BB,  partially  vol.  with  strong  ammoniacal  odour.  If  pure, 
no  lines  in  spectroscope. 

MAGNESIA  ALUM  (Pickeringite) :  MgO,  APO*,  SO3,  IPO.  In 
white  or  greyish  crusts,  &c.  If  pure,  no  lines  in  spectroscope. 

ALUNOGENE  (Hair-salt  in  part)  :  APO8  15-4,  SO3  36,  H2O  48-6. 
In  efflorescences  of  minute  acicular  crystals  on  various  coals,  shales. 
Ac.  Normally  colourless,  but  often  gre  nish  or  brownish  from 
admixture  with  iron-vitriol  or  iron-alum. 

( The  residuum,  left  BB  on  charcoal,  assumes  by  ignition  with  cobalt  solution 
aJlesJi-red  colour). 

REUSSIN  :  A  compound  of  soda  sulphate  (Mirabilite)  with  30-31 
per  cent,  of  magnesia  sulphate.  In  white  feathery  crusts,  &c. 
Colours  flame  intensely  yellow. 

EPSOMITE:  MgO  16-26,  SO3  32-52,  H2O  51-22.  Rh.  (V  :  V  90°38') 
but  commonly  efflorescent,  &c. ;  colourless ;  H  (crystals)  2-2-5  '> 
G  l-7-l"8.  After  strong  ignition,  gives  alkaline  reaction.  If  pure, 
no  lines  in  spectroscope. 

BLCEDITE  (Astrakanite) :  Na2O  18-65,  MgO  11-95,  SO3  47'90, 
H2O  21-50.  Clino-Rh.,  but  mostly  in  lamellar  masses,  crusts,  &c. 
H  (crystals)  2-5-3-5  ;  G  2-2-2-3.  White,  grey,  pale-reddish,  greenish, 
&c.  Colours  flame  intensely  yellow.  LCEWITE  is  a  related  soda- 
magnesia  sulphate,  but  apparently  distinct  in  crystallization,  and 
with  only  14*66  per  cent,  water. 

KAINITE :  MgO,  SO3  48-3,  KC1  30,  H2O  21-7..  Clino-Rh.  (tabular), 
but  commonly  in  granular  masses,  <fec.  H  2*5  ;  G  2'13.  Yellowish- 
white,  greyish.  BB,  with  phosphor-salt  and  CuO,  strong  chlorine 
reaction  (azure  flame).  Part  of  the  KC1  sometimes  replaced  by 
NaCL 


MINERAL   TARLES  I — XVI.  155 

( The  residuum,  left  BB  on  charcoal,  assumes  by  ignition  with  cobalt  solution  a 

light- green  colour). 

GOSLABITE  :  ZnO  28-22,  SO3  27-88,  H2O  43-90.  Rh.  (V :  V 
91  °5').  H  (crystals)  2-2-5  ;  G  2-0-2-1;  colourless,  greyish-white* 
BB,  with  carb.  soda,  gives  zinc  sublimate  on  charcoal. 

(The  residuum,  on  charcoal,  with  <x>balt  solution  becomes  on  ignition  dark-grey. 

In  spectroscope,  Ca  (or  Ca  and  K)  lines). 
POLYHALLITE  ;    SYNGESITE  j    ETTRINGITE  ;    KlESERITE  :     Soluble   in 

part  only,  or  very  slowly  sol.     Taste,  very  feeble.     See  below, 
tf  Insol.  or  very  slowly  sol.  in  water.     Taste,  0,  or  very  feeble. 

(BB,  imparts  a  green  colour  to  the  flame-point,  and  gives  PJ05  reaction  (yellow 
precipitate)  with  amm.  molybdate  in  the  nitric  acid  solution). 

SVANBERGITE  :  Na2O,  CaO,  APO3,  SO3,  P205,  H2O  6  per  cent. 
Hemi-Hex.  (RR  about  88°  or  90°)  j  H  4-5;  G  2-57.  Yellow, 
orange-red.  Very  rare,  and  imperfectly  known. 

(BB,  with  Co-solution,  a,  bright  blue  colour). 

ALUMINITE  (Websterite)  :  A12O3  29-77,  SO3  23-23,  H2O  47.  In 
white  or  yellowish-white  earthy  or  porous  masses  which  adhere  to 
the  tongue  ;  H  1-0;  G 1-7-1 '8.  BB,  infusible  ;  evolves  SO2.  FELSO- 
BANYITE,  in  small  groups  of  rhombic  (pseudo-hexagonal)  tabular 
crystals,  is  related  in  composition,  but  yields  38-67  per  cent,  water. 

ALUNITE  (Alumstone)  :  K2O  11-33,  A12O3  37-10,  SO3  38-56,  H20 
13-01.  Hemi-Hex.  (R  :  R  89al  0'),  but  commonly  in  granular  masses. 
H  4-5  ;  G  2-6-2-8.  White,  pale-reddish,  yellowish,  &c.  Infusible; 
generally  decrepitates.  Evolves,  on  strong  ignition,  SO2.  LCEWIGITE 
is  identical  or  closely  related,  but  yields  18-18-5  per  cent,  water. 

(BB,  with  Co-solution,  a  flesh-red  colour). 

KIESERITE  :  MgO  29,  SO3  58,  H2O  13,  but  commonly  yields  more 
water,  from  hygroscopic  absorption.  Clino-Rh.,  but  commonly  in 
fine-granular  masses.  H  3 ;  G  2*57.  Very  slowly  soluble  in  water. 
BB,  infusible  ;  gives  off  SO2. 

(BB,  with  Co-solution,  a  dark-grey  colour.  In  spectroscope,  Ca  (orCaandK)  lines)*. 

GYPSUM  (Selenite):  CaO  32-54,  SO3  46-51,  H2O  20-95.     Clino-Rh. 

(See  note  at  close  of  Table).     H  1-5  j  G  2-2-2-4.     Colourless,  white, 

*  These  spectrmn-lines  come  out  most  distinctly  when  the  ignited  test-substance  is  moistened 
by  hydrochloric  acid.    See  Outline  of  Blowpipe  Practice,  pp.  55-59. 


156  BLOWPIPE    PRACTICE. 

pale-reddish,  bluish,  yellowish,  &c.;  streak,  white;  aspect  vitrio- 
pearly  in  crystallized  and  lamellar  examples,  silky  in  most  fibrous 
varieties,  sometimes  earthy.  In  thin  pieces,  somewhat  flexible.  BB, 
becomes  immediately  opaque,  and  fuses  into  an  opaque  white  bead. 
On  prolonged  ignition,  reacts  alkaline,  and  tinges  the  flame-border 
distinctly  red. 

POLYHALLITE  :  K20,  SO3  28«93,  CaO,  SO  45-17,  MgO,  SO3  19-92, 
H20  5-98.  Rh.,  but  commonly  fibrous,  lamellar,  &c.  H  3-3-5  ;  G 
2-7-2-77.  Red,  flesh-red,  greyish,  colourless.  Partly  sol.  in  water. 
Taste,  feebly  bitter.  BB,  very  easily  fusible  into  an  alkaline  (hollow) 
bead.  Some  examples  give  Cl-reaction  with  phosphor-salt  and  CuO. 

SYNGENITE  :  K2O,  SO3,  CaO,  SO3,  with  5-5  per  cent,  water.  Clino- 
Rh.  (tabular);  H  2-5  ;  G  2-6  ;  colourless.  BB,  easily  fusible,  but 
generally  decrepitates.  Partly  soluble  in  water.  Distinguished  chemi- 
cally from  Polyhallite  by  absence  of  MgO.  (See  Outline  of  Blowpipe 
Practice,  page  55). 

ETTRINGITE  :  CaO,  APO3,  SO3,  H20  (45-82  per  cent.).  In  delicate, 
silky,  hexagonal  prisms  on  the  lava  of  the  Laacher  See.  G  1*75. 
BB,  swells  up,  but  remains  unfused.  Partly  soluble  in  water. 

BS.— FORMING,  BB,  WITH  BORAX  A  STRONGLY  COLOURED  BEAD. 

t  Soluble  or  partly  sol.  in  water,  and  possessing  a  metallic  or  other  taste. 

(Cu  reaction). 

CHALCANTHITE  or  BLUE  VITRIOL.  CuO  31-85,  SO8  32-07,  H2O 
36-08.  Anorthic,  but  commonly  in  drusy  or  earthy  crusts  of  a  blue 
or  greenish-blue  colour  ;  .  streak  bluish-white  ;  H  (crystals)  2*5  ; 
G  22-2-3.  Taste,  strongly  cupreous  and  unpleasant.  Moistened 
and  rubbed  on  a  knife-blade,  deposits  metallic  copper.  PISANITE  is 
a  cupreous  Iron- Vitriol  or  Melanterite.  LETTSOMITE  and  WOOD- 
WARDITE  are  hydrated  sulphates  of  CuO  and  APO3.  The  first  occurs 
in  druses  of  deep-blue  hair-like  crystals ;  the  second  in  mammillated 
examples  of  similar  colour. 

(Fe  reaction*,  BB,  a  magnetic  slag), 

MELANTERITE  or  GREEN  VITRIOL  :  FeO  25-90,  SO3  28-78,  H2O 
45 '32.  Clino-Rh.,  but  commonly  in  crusts  and  coatings  on  iron 
ores,  <fec.  Pale-green,  blue-green,  often  ochreous  on  surface.  H 

*  The  solution  yields  with  Ferricyanide  of  potassium,  or  with  the  ferrooyanide,  a  deep-blue 
precipitate. 


MINERAL    TABLES  :— XVI.  157 

(crystals)  2;  G  1-8-1 -9.  Taste,  inky,  metallic.  PISANITE  is  a 
cupreous  variety.  TAURISCITE  a  rhombic  variety  isomorphcus  with 
Epsomite. 

COQUIMBITE  :  F208  28-47,  SO8  42-70,  H2O  28-83.  Hex.,  but  com- 
monly in  small  granular  masses.  •  H  2-2*5  ;  G  2-2-1  ;  very  pale  green, 
bluish,  greenish-white.  Taste  metallic,  inky.  The  aqueous  solution 
deposits  Fe208  on  boiling. 

BOTRYOGENE:  MgO,  FeO,  Fe203,  SO8,  H2O  (28-30  per  cent.). 
Cliiio-Rh.,  fibro-mamillated,  &c.  Red,  orange  or  brownish-yellow ; 
streak  yellow;  H  (crystals)  2-2-5;  G  2-1.  Taste,  feebly  metallic. 
Partly  soluble  in  water.  RCEMERITE  is  closely  allied  or  identical,  but 
part  of  the  FeO  is  replaced  by  ZnO. 

IRON-ALUM  (Feather  Alum ;  Halotrichite,  in  part) :  Composition 
very  variable,  but  essentially  an  alum,  with  FeO  and  Fe203  largely 
replacing  the  other  bases.  Greenish  or  brownish,  in  coatings  and 
minute  hair-like  crystals.  See  under  ALUNOGENE  in  B1  f,  above. 

VOLTAITE  :  FeO,  Fe2O3,  APO3,  SO8,  H2O  (15-3  per  cent.).  An 
altered  Iron-Alum  ?  Reg. ;  dark-green,  black ;  streak,  greenish -grey. 
H  2-5-3-0  ;  G  2-8.  Slowly  soluble  in  water.  Taste,  feebly  metallic. 

Other  ferruginous  sulphates,  Glockerite,  Pissophane,  Apatelite, 
Copiapite,  Jarosite,  &c.,  are  insoluble  or  very  slightly  soluble  in 

water.     See  below. 

(Go  reaction). 

BIEBERITE  (Cobalt  Yitriol) :  CoO,  SO3,  H20,  but  part  of  CoO  often 
replaced  by  FeO  or  MgO.  Isomorphous  with  Melanterite,  but  occurs 
only  in  efflorescent  coatings  of  a  pale  rose-red  colour.  Easily  dis- 
tinguished by  its  blue  borax-glass. 

(Ni  reaction). 

MORENOSITE  (Nickel  Vitriol).  NiO  (MgO),  SO3,  H2O  (40-45  per 
cent.).  Isomorphous  with  Epsomite,  but  occurring  only  in  efflo- 
rescences of  hair-like  crystals  or  in  amorphous  coatings.  Green, 

greenish-white. 

( Uranium,  reaction). 

JOHANNITE  :  UO,  SO3,  H2O.  Clino-Rh. ;  H  2-2-5;  G  3-2.  Grass- 
green;  streak  paler.  Slowly  soluble  in  water.  Various  other  uranium 
sulphates  (in  some  of  which  U2O3  is  present)  have  been  recognized 
(Medjidite,  Zippeite,  Voglianite,  &c.),  but  the  composition  of  these 
is  more  or  less  inconstant,  and  their  characters  are  very  imperfectly 
known. 


159  BLOWPIPE    PRACTICE. 

(Mn  reaction). 

APJOHNITE  (Manganese  Alum) :  Essentially  an  alum  with  MnO 
replacing  part  of  the  other  bases.  In  hair-like  efflorescences  of  a 
pale  reddish  or  brownish  colour. 

FAUSERITE  (Manganese  Vitriol)  :  MnO,  MgO,  SO8,  H2O  (42-66 
per  cent.).  Rh.  (V:V  91°  18');  H  2-2-5 ;  G  1-9.  Pale  reddish, 
yellowish-white. 

f  f  InsoluUe,  (or  practically  insol.y  in  water.     Taste,  0,  or  very  slight. 

(Pb  and  Cu  reactions.  BB\  on  charcoal  a  yellow  coating). 
LINARITE:  PbO  55'7,  CuO  19-8,  SO3  20,  H2O  4-5.     Clino-Rh. ; 
H  2-5-3;  G  5-3-4-45.     Azure-blue;  streak  pale-blue. 

(Cu  reaction). 

BROCHANTITE  :  CuO  70-34,  SO8  17-71,  H20  11-95.  Rh.  1  jT:V 
104°  32');  H  3-5-4  ; .  G  3-8-3-9.  Emerald-green,  dark-green ;  streak 
pale-green.  KRISUVIGITE  is  identical.  TANGITE  and  WARRINGTONITE 
are  closely  related,  but  yield  15*33  per  cent,  water.  All  form  a 
deep-blue  solution  with  ammonia. 

LETTSOMITE  (Velvet  Copper  Ore).  CuO,  APO8,  Fe'O2  SO8,  H2O 
(2.3*34  per  cent.).  In  delicate  hair-like  crystals  of  a  deep  blue  colour. 
WOODWARDITE,  in  blue  mamillated  masses,  is  identical. 

(Fe  reaction:  BB,  a  magnetic  slag  or  crust). 

COPIAPITE  :  Fe208,  SO8,  H20  24-5  per  cent.  In  six-sided  pearly 
tables,  and  granular  masses.  H  1-5;  G  2-14.  Yellow. 

STYPTICITE  :  Fe2O3,  SO3,  H2O  36  per  cent.  In  greenish  or  yellowish- 
white  fibrous  crusts.  FIBRO-FERRITE  is  apparently  identical,  but  some 
so-called  Fibro-ferrites  are  soluble  in  water.  Owing  to  their  incon- 
stancy of  composition,  due  to  alteration  and  intermixture,  no  very 
strict  definitions  ai  e  possible  as  regards  ferruginous  sulphates  generally. 

GLOCKERITE:  Fe2O8,  SO-',  H20  (20*7  per  cent.).  Stalactitic,  botry- 
oidal.  Black,  dark-brown,  yellowish,  dark-green;  streak  brownish- 
yellow.  PISSOPHANE,  in  dark-green  and  brown  botryoidal  and  earthy 
masses,  is  apparently  a  variety,  or  a  closely  related  substance,  but 
yields  40-41  per  cent,  water.  VITRIOL-OCHRE  is  an  earthy,  ochre- 
yellow  variety  (H2O  21  per  cent.). 

APATELITE:  Fe208,  SO8,  H2O  (4  per  cent.).  In  small  nodular 
earthy  masses  of  a  yellow  colour  and  streak,  from  Auteuil,  near  Paris. 
Chiefly  distinguished  by  its  low  amount  of  water. 


MINERAL   TABLES  : XVI.  159 

JAROSITE  :  K2O  9-38,  Fe'O'  47-91,  SO3  31-93,  H2O  10-78.  Hemi- 
Hex.  (R :  R  about  89°),  mostly  tabular  from  predominance  of  the 
basal  plane,  also  in  scaly  and  fine  granular  examples ;  H  3-4 ;  G 
3 '2-3 -6.  Dark-brown,  brownish-yellow,  red  by  transmitted  light ; 
streak  ochre-yellow.  Shews  the  red  K-line  in  spectroscope. 

DIADOCHITE:  FeW,  SO8,  P205,  H2O  30-3  per  cent.  H  2-5-3; 
G  l-9-2'5.  Brown,  brownish-yellow;  streak  somewhat  lighter. 
Mostly  in  mammillated,  concentric-lamellar  examples.  BB,  on  char- 
coal, a  magnetic  bead.  In  the  forceps,  tinges  the  flame-point  green. 
PITTICITE  (Iron  Sinter)  resembles  Diadochite  in  general  characters, 
but  contains  As206.  The  composition,  however,  varies  greatly  in 
different  examples. 

NOTE  TO  TABLE  XVI. 

This  Table  is  composed,  apart  from  a  few  sulphides  of  non-metallic  aspect, 
entirely  of  sulphates. 

Sphalerite  or  Zinc  Blende  is  the  only  commonly-occurring  sulphide  referred 
to  in  the  Table.  This  mineral  presents  in  many  of  its  varieties  a  more  or  less 
metallic  lustre  ;  but  in  others,  the  light-coloured  varieties  especially,  the  lustre 
is  non-metallic  and  usually  adamantine.  Sphalerite  is  commonly  in  lamellar 
masses  (of  easy  cleavage  parallel  to  the  planes  of  the  rhombic  dodecahedron), 
or  otherwise  in  crystals  of  the  Regular  System.  These  consist  chiefly  of 
tetrahedrons,  twinned  octahedrons,  rhombic-dodecahedrons,  and  a  com- 
bination of  rhombic-dodecahedron  with  a  half-trapezohedron  or  pyramidal 

0.0 

tetrahedron .     Sub-fibrous  and  granular  examples  are  also  known,  and 

some  of  these,  more  especially,  are  cadmiferous.  Certain  Blendes,  likewise, 
contain  thallium  in  minute  quantity  ;  and  in  almost  all  the  dark  Blendes  small 
proportions  of  Fe  and  Mn  are  present.  Many  varieties  also  contain  traces, 
and  even  workable  amounts,  of  gold  and  silver.  The  more  common  colours 
are  dark-brown  and  black,  with  light-brown  streak,  and  these  dark  examples 
are  often  blood-red  in  thin  pieces  by  transmitted  light.  Less  common  colours 
are  dark-green  and  yellow:  colourless  examples  are  still  more  rare,  and 
hitherto  have  been  found  only  in  New  Jersey.  Yellow  varieties  (especially) 
often  shew  strong  phosphorescence  when  scratched  or  abraded  in  the  dark. 
All  varieties  give  a  zinc-sublimate  on  charcoal  if  fused  in  powder  with  carb. 
soda  and  borax  ;  and  all  emit  the  odour  of  sulphuretted  hydrogen  when  warmed 
in  powder  with  hydrochloric  acid. 

Natural  sulphates  fall  into  five  more  or  less  well  defined  groups.  These 
comprise  :  (1)  Anhydrous  Prismatic  Sulphates  ;  (2)  Gypsums ;  (3)  Bitter-Salts 
and  Vitriols  ;  (4)  Alums  ;  and  (5)  Alumstones. 

The  anhydrous  prismatic  sulphates  are  principally  represented  by  Anglesite, 
Barytine,  Celestine,  and  Anhydrite.  These  have  the  common  formula  RO, 


160 


BLOWPIPE   PRACTICE, 


SO8,  and  a  common  Rhombic  crystallisation,  with  V  :  V  (the  prism-angle  in 
front)  100°  30'— 104°  30\  according  to  the  species. 

Anglesite  (PbO,  SO8)  occurs  in  small  crystals,  mostly  colourless  or  greyish, 
with  strong  adamantine  lustre  ;  and  also  in  small  mamillated  and  lamellar 
examples,  and  in  earthy  masses,  white,  yellowish,  &c.,  arising  from  decom- 
position of  galena.  The  crystals  are  generally  in  drusy  aggregations,  and  are 
very  brittle.  They  are  either  tabular,  from  predominance  of  B  or  V ;  prismatic, 
vertically,  from  predominance  of  V ;  prismatic,  transversely,  from  extension 
of  i  P  or  £  P  ;  or  pyramidal  from  preponderance  of  P.  It  much  resembles  the 
lead  carbonate  cerussite,  but  is  distinguished  (when  the  two  are  not  intermixed) 
by  blowpipe  and  acid  reactions. 

Barytine  or  Heavy  Spar,  sulphate  of  baryta,  is  very  widely  distributed,  and 
is  especially  abundant  as  a  gangue  or  veinstone  in  lead,  zinc,  silver,  and  other 
metallic  veins.  It  occurs  most  commonly  in  lamellar  or  fibrous  masses,  but  is 
also  very  common  in  crystals.  The  latter  are  sometimes  of  comparatively  large 
size,  and  are  almost  always  sharply-defined  and  distinct.  They  belong  to  the 

Rhombic  System,  and  present  chiefly  four  leading  types  :    (1)  tabular,  with  V 

•— -  \j 

and  B,  or  rectangular-tabular  with  £  P,  P,  and  B,  as  principal  forms,  B  pre- 
dominating ;  (2)  transversely  prismatic  in  a  macro-diagonal  direction,  with  V 
and  i  P  as  chief  forms,  the  latter  elongated ;  (3)  transversely  prismatic  in  a 

brachy-diagonal  direction,  with  4  P  and  P  as  chief  forms,  the  latter  elongated ; 
and  (4)  pyramidal,  from  about  equal  predominance  of  the  common  front  and 

side  polars  £  P  and  P.  More  common  angles  are  as  follows  :  V :  V  101°  40' ; 
i  P :  £T  over  summit  102°  17' ;  B  :  £  P  141°  8' ;  P  :  P  over  summit  74°  36' ; 

B :  P  127°  18'.  Barytine  is  commonly  colourless,  white,  or  yellow,  but  also 
frequently  grey,  reddish,  bluish,  &c.,  and  in  some  stalactitic  and  radio- 
spherical  examples,  deep-brown  or  greyish-black.  BB,  it  melts  into  a  bead 
which  reacts  alkaline  after  prolonged  ignition,  and  it  communicates  to  the 
flame-border  the  apple-green  tint  characteristic  of  barium  compounds.  In 
carb.  soda,  BB,  it  is  rapidly  and  entirely  dissolved.  In  acids,  insoluble.  In 
Bunsen  flame,  after  sufficient  ignition,  it  shews  the  green  bands  of  the  barium 
spectrum  very  distinctly. 

Celestine,  the  strontia  sulphate,  differs  remarkably  from  Barytine  in  its 
geological  relations,  occurring  very  rarely  in  metallic  veins,  but  chiefly  in 
cavities  and  fissures  in  stratified  calcareous  rocks.  The  finest  crystals  occur 
in  connection  with  native  sulphur  in  Sicily.  These  are  colourless,  but  when 
in  fibrous  or  lamellar  masses  celestine  very  commonly  presents  a  pale-blue 
colour,  whence  its  name.  It  is  also  white,  pale-yellowish,  &c.  The  crystals 
are  Rhombic  combinations,  and  are  generally  elongated  in  the  direction  of  the 

brachy-diagonal.  More  common  forms  comprise  B,  V,  P,  and  %  P,  with  angles 
as  follows  :  V  :  V  about  104°,  but  varying  from  103°  30'  to  104°  30' ;  P :  P  over 

summit  75°  52' ;  B :  P  127°  56' ;  £  P  :  i  P~62°  40' ;  B  :  £  F 121°  20'.  BB  melts, 
colours  the  flame-border  crimson,  and  reacts  alkaline.  Entirely  dissolved, 


MINERAL   TABLES  : — XVI.  161 

BB,  by  carb.  soda.  Insoluble  in  acids.  In  Bunsen  flame,  after  short  ignition, 
shews  very  distinctly  the  blue,  orange-red,  and  group  of  crimson  lines,  of  the 
strontium  spectrum.  These  lines  come  out  still  more  prominently  by  crushing 
the  ignited  or  fused  bead  (as  obtained  in  a  reducing  flame  on  charcoal),  and 
moistening  the  powder  with  hydrochloric  acid. 

Anhydrite,  lime  sulphate,  is  generally  in  lamellar,  granular  or  columnar 
masses  of  a  white  colour,  though  occasionally  greyish  or  bluish,  and  sometimes 
brick-red.  Crystals  are  comparatively  rare.  They  consist  chiefly  of  com- 
binations of  V  and  V  with  several  brachydomes  or  side-polars,  V  predominating 
and  imparting  to  the  crystals  a  rectangular,  tabular  aspect.  Also  of  com- 
binations of  V  and  P,  with  brachy  diagonal  elongation.  BB,  fuses  easily  into  an 
alcaline  reacting  bead,  which  imparts  a  comparatively  feeble  but  distinct  red 
colour  to  the  flame  border.  In  carb.  soda,  BB,  not  dissolved.  Slowly  soluble 
in  hydrochloric  acid.  In  the  Bunsen  flame  (especially  if  first  ignited  and  then 
moistened  with  hydrochl.  acid),  it  shews  the  green  and  red  lines  of  the  calcium 
spectrum  very  distinctly. 

The  Gypsum  Group  consists  of  hydrated  sulphates,  with  lime,  or  lime- 
magnesia,  and  alkalies,  for  base.  It  is  chiefly  represented  by  Gypsum  and 
Polyhallite, 

Gypsum,  in  analytical  formula,  CaO,  SO3  4-  2  H2O,  is  a  widely  distributed 
mineral.  It  occurs  chiefly  in  Clino- Rhombic  crystals  and  in  lamellar,  laminar, 
fibrous,  columnar,  and  granular  masses,  either  colourless,  or  of  a  white,  reddish, 
yellowish  or  other  tint,  and  occasionally  red,  brown,  black,  &c.,  from  ochreous 
or  carbonaceous  admixtures.  Small  transparent  pieces  become  immediately 
opaque  if  held  at  the  edge  of  a  candle  flame,  and  all  varieties  may  be  scratched 
by  the  nail.  The  crystals  are  often  of  considerable  size.  The  most  common, 
perhaps,  are  combinations  of  the  Vertical  prism  V  with  the  Side-vertical  or 

/ 
Olino-pinakoid  V,  and  the  Hemi-pyramid  P.     The  latter  form  occurs  necessarily 

as  a  pair  of  inclined  planes  (often  curved)  at  each  extremity  of  the  crystal. 

The  V  or  side  planes  usually  predominate,  and  thus  give  a  somewhat  flattened 
aspect  to  most  crystals.  Two  of  these  crystals  are  frequently  united  in  reversed 
positions,  producing  arrow-headed  or  lance-headed  twins.  Transparent 
examples  of  Gypsum  are  commonly  known  as  Selenite.  The  lustre  is  partly 
pearly  and  partly  vitreous,  and  in  most  fibrous  examples,  satin-like.  The 
ignition-loss  (water)  is  nearly  21  per  cent.  In  the  Bunsen  flame,  the  red  and 
green  lines  of  the  calcium  spectrum  come  out  very  prominently,  especially  if 
the  ignited  test-matter  be  moistened  with  a  drop  of  -hydrochloric  acid. 
Gypsum,  although  tasteless,  and  thus  for  practical  purposes  regarded  as  in- 
soluble, is  dissolved  in  fine  powder  by  about  450  parts  of  water. 

Polyhallite  (see  composition  in  Table)  is  comparatively  i unimportant.  It 
occurs  commonly  in  sub-fibrous  or  columnar  masses  of  .a  pale  reddish  or 
greyish  colour.  In  water  it  is  partially  dissolved,  a  residuum  of  lime  sulphate 
remaining.  Very  easily  fusible.  Ignition-loss  undervSjaer  cent.,  but  examples 
are  often  mixed  with  clay,  gypsum,  &c. 
12 


162  BLOWPIPE    PRACTICE, 

The  group  of  Bitter-Salts  and  Vitriols  falls  into  three  sections  :  a  rhombic 
section,  with  the  analytical  formula  RO,  SO3  -f  7  H2O,  represented  by  Epsomite, 
Goslarite,  Morenosite ;  a  elino-rhombic  section,  represented  by  Melanterite. 
Bieberite,  &c.,  al*o  with  the  formula  RO,  SO3  +  7H'O;  and  a  triclinic  or 
anorthic  section,  with  the  formula  RO,  SO'  +  SH'O,  represented  by  Chalcanthite 
or  Copper  Vitriol.  These  compounds  in  their  actual  occurrence  as  minerals, 
however,  are  of  comparatively  little  interest,  as  they  occur  chiefly  in  solution 
or  in  the  condition  of  efflorescent  coatings,  &c.,  rarely  in  distinct  crystalliza- 
tions. All  possess  an  intensely  bitter  or  metallic  taste,  and  give  off  sulphurous 
acid  on  strong  or  prolonged  ignition.  The  water,  evolved  in  the  bulb  tube, 
has  thus  an  acid  reaction. 

The  group  of  Alums,  characterized  by  octahedral  crystallization  and  the 
general  formula  RO,  S03  +  R203,  3S03  +  24HaJ,  is  represented  primarily  by 
ordinary  or  potassic  alum,  and  subordinately  by  soda  alum,  magnesia  alum, 
iron  alum,  &c.  These  compounds  in  their  'natural  occurrence,  present  them- 
selves merely  in  efflorescent  crusts  and  coatings,  and,  as  minerals,  are  of  no 
special  interest.  All  are  soluble  and  sapid,  and  evolve  SO2  on  strong  ignition. 
The  alum  of  commerce  is  essentially  a  manufactured  product,  derived  chiefly 
from  decomposing  pyritous  shales. 

The  Alumstones  are  insoluble  aluminous  sulphates,  represented  chiefly  by 
Alunite  and  Aluminite  or  Websterite.  Alunite  is  a  rhombohedral  potassic 
species,  occurring  essentially  in  connection  with  volcanic  or  trachytic  rocks. 
It  differs  from  most  sulphates  by  its  hardness,  which,  in  granular  varieties 
especially,  often  exceeds  that  of  fluor  spar.  It  is  infusible,  but  becomes 
decomposed  on  strong  ignition,  and  evolves  SO2.  In  the  Bunsen  flame 
(^specially  if  the  ignited  test-matter  be  moistened  by  hydrochloric  acid),  it 
shews  the  red  line  of  the  K-spectrum  very  distinctly.* 

Aluminite  or  Websterite  is  of  little  importance.  It  is  a  simple  sulphate  of 
alumina  with  47  per  cent,  water,  mostly  in  white  or  yellowish-white  earthy  or 
nodular  masses,  which  adhere  strongly  to  the  tongue  and  are  scratched  by  the 
finger-nail.  BB,  infusible,  but  evolves  SO2. 

*  See  PART  I.,  page  58,  59. 


TABLE    XVII. 


[Lustre  non-metallic.     Easily  soluble,  BB,  in  borax  or  phosphor-salt.     Nitric- 
acid  solution  (on  warming)  yielding  yellow  precipitate  with  amm.  molybdate.] 

A>  — Fluo-Phosphates  -Chloro-Phosphates.  Giving, in  powder, 
with  sulphuric  acid  in  glass  tube,  strong  fluorine-reac- 
tion ;  or  with  phoephor-salt  and  copper  oxide,  BB,  an 
azure  flame-coloration. 

A*.— YIELDING  METALLIC  LEAD,  BB,  WITH  GARB.  SODA  ON  CHARCOAL. 

PYROMORPHITE  :  PbO  P20*  89*7,  PbCl2  10-3,  but  part  of  the  PbO 
sometimes  replaced  by  CaO,  part  of  the  P2O5  by  As205,  and  part  of 
the  PbCl2  by  CaFl2.  Hex.;  H  3-5-4;  G  6-9-7-0;  green  of  various 
shades,  light  or  dark  brown,  ash-grey,  rarely  yellow  or  colourless. 
BB,  melts  into  a  bead  which  crystallizes  with  broad  surface-facets  on 
cooling.  See  Note  at  close  of  present  Table. 

A*.—  INFUSIBLE,  OR  FUSIBLE  ON  EXTREME  EDGES  ONLY. 

APATITE:  var.  1,  F  luor- Apatite :  CaO,  P2O5  92-27,  CaFl2  7'73  : 
var.  2,  Ghl^ApaJbite:  CaO,  P2O5  89-34,  CaCl2  10'66.  But  in  var. 
1,  a  small  amount  (usually  0-20-0-60  per  cent.)  of  Ca(  I5  is  commonly 
present;  whilst  in  var.  2,  the  GaCP  is  almost  always  largely  replaced 
by  CaFl2,  the  latter  usually  averaging  4  or  nearly  5  per  cent,  of  the 
entire  components  of  the  apatite.  Crystal-System  Hex. ;  H  5*0  ; 
G  2-9-3-3  ;  green  of  various  shades,  greenish- white,  light-red,  reddish 
or  chocolate  brown,  sometimes  colourless.  BB,  practically  infusible, 
or  rounded  only  on  the  thinnest  edges.  Phosphorite,  Francolite, 
Osteolite,  Talc-apatite,  Eupychroite,  are  merely  varieties  (in  some 
cases  more  or  less  decomposed)  of  apatite  proper.  In  these,  as  well 
as  in  many  unaltered  crystals,  <fcc.,  intermixed  carbonate  of  lime  is 
often  present.  See  Note  at  close  of  present  Table. 

WAGNERITE:  MgO,  P'O5,  81,  MgFl2  19.  Clino-Rh. ;  H  5-5-5; 
G  3-0-3-15  ;  yellow,  yellowish- white.  BB,  fusible  on  thin  edges  only. 
Very  rare.  The  Norwegian  Kjerulfin  is  closely  related,  if  not  an 
altered  variety. 

A*. -VERY  EASILY  FUSIBLE. 
(Strong  Mn  reaction  with  carb.  soda). 

TRIPLITE:  (FeO,  MnO)  P  O5,  R  Fl2.  Clino-Rh  J;  H  5-5-5;  G 
3-6-3-9;  dark-brown;  streak  yellowish-grey.  Occurs  only  in  ch  avable 


164  BLOWPIPE    PRACTICE. 

masses  of  vitreo-resinous  lustre.  Easily  fusible  into  a  dark  globule. 
With  carb.  soda,  strong  manganese-reaction.  Zwieselite  is  closely 
related,  but  is  apparently  Rhombic  in  crystallization. 

(Bed  flame-coloration,  and  distinct  Li-line  in  spectroscope). 

AMBLYGONITE:  APO3,  P2O5,  (LiNa)'  Fl.  Anorthic;  H  6;  G 
3-0-3-12;  greenish-white,  greyish  or  bluish-green.  Easily  fusible 
into  a  white  opaque  bead,  with  red  coloration  of  the  flame.  With 
cobalt-solution,  after  ignition,  assumes  a  fine  blue  colour.  HEBRONITE 
(Montebrasite)  is  closely  allied,  but  yields  water  on  ignition.  Perhaps 
an  altered  amblygonite  ] 

^%The  imperfectly  known  HERDERITE  or  ALLOOONITE  (Rh.,  with  pseudo- 
hexagonal  aspect ;  yellowish- white ;  H  5 ;  G  2*9-3),  and  some  varieties  of 
WAVELLITE  (mostly  in  greenish-white  or  green  radiated  fibrous  examples,  see 
under  D,  below),  are  also  fluorine-containing  phosphates.  These  assume  a  fine 
blue  colour  after  ignition,  in  powder,  with  nitrate  of  cobalt.  KAKOXENE,  in 
yellow  silky  tufts  (see  under  C1,  below),  shews  also,  in  most  examples,  a  slight 
fluorine-reaction.  BB,  a  magnetic  slag. 

B.— No  Fluorine  reaction.    No  water  evolved  by  ignition  in 

bulb-tube- 

Bl.— EASILY  FUSIBLE. 
(Fusion-globule  magnetic). 

TRIPHYLINE:  Li2O,  Na'O,  K2O,  MnO,  FeO,  P205.  Rh.,  but 
occurring  only  in  cleavable  masses  of  a  greyish-green,  light  grey,  or 
grey-blue  colour.  H  4-5 ;  G  3-5-3-6.  Colours  the  flame  distinctly 
red,  if  moistened  with  hydrochloric  acid,  or  fused  with  chloride  of 
barium,  and  shews  the  red  Li-line  in  spectroscope.* 

B2  —  INFUSIBLE,  OR  FUSIBLE  ON  EXTREME  EDGES  ONLY. 

XENOTIME:  YO  62-13,  P'O5  37-87,  but  with  part  of  the  YO 
always  replaced  by  CeO.  Tetr. ;  H  4-5 ;  G-  4-45-4-6;  yellowish, 
brown,  red-brown,  pale-red.  Scarcely  attacked  by  boiling  acid ;  but, 
on  dilution  with  water,  sufficient  is  dissolved  to  give  a  yellow 
coloration  to  a  fragment  of  amm.  molybdate  dropped  into  the  solution 
and  gently  warmed. 

CRYPTOLITE  :  CeO,  LnO,  DiO,  P'O5.  Pale-yellow  or  reddish ;  G 
4'6;  in  minute  acicular  crystals  in  certain  Apatites.  PHOSPHOCERITE, 

*  Some  examples  of  Triphyline  shew  this  crimson  line  very  distinctly  per  se,  but  in  general 
it  is  only  obtained  by  moistening  the  mineral  with  hydrochloric  acid,  or  mixing  it  in  powder 
with  chloride  of  barium.  The  latter  reagent  answers  perfectly,  and  has  the  advantage  of  being 
conveniently  carried  in  the  blowpipe  case. 


MINERAL   TABLES  : — XVII.  165 

in  very  minute,  apparently  Tetragonal,  crystals  in  certain  Swedish 
examples  of  cohaltiae>  is  identical  in  composition.  G  4*78  j  pale 
greenish-yellow. 

MONAZITE:  CeO,  LnO,  ThO,  3PfO*.  Clino-Rh. ;  H  5-5-5;  G 
4 -9-5 -3;  reddish-brown,  yellowish-red,  pale-red.  Many  examples 
give  traces  of  tin  by  the  reducing  process :  See  page  1 7.  EREMITE 
(MONAZITOID)  and  TURNESITE  are  varieties.  In  some  of  these  & 
small  percentage  of  Tantalic  acid  is  present. 

C.— Hydrous  Phosphates.    Water  evolved  on  ignition 
in  bulb-tube. 

GI.— MAGNETIC  AFTER  FUSION  OR  IGNITION,  OR  GIVING  STRONG  REACTION  OF 
MANGANESE  WITH  CARB.  SODA. 

(This  section  includes  a  series  of  iron  or  manganese-phosphates,  in  most  of 
which  the  composition  is  very  uncertain,  owing  to  changes  in  the  oxidation  of 
the  base,  or  loss  or  gain  of  water.  Many  of  these  phosphates  can  scarcely 
rank  as  definite  species.  In  the  present  Table  they  are  arranged  after  the 
average  percentage  of  water  which  they  contain.  Where  the  iron  is  in  the 
condition  of  protoxide,  the  ignition-loss  will  necessarily  be  slightly  lower 
(about  1  per  cent.)  than  the  actual  percentage  of  water  present  in  the  mineral). 

KAKOXENE:  Fe2O3  47,  P'O5  21,  H2O  32.  In  delicate  tufts  and 
fibro-mammillated  examples  of  a  yellow  colour  with  silky  lustre.  G 
2 -4.  BB,  a  dark  magnetic  slag. 

VIVIANITE  :  FeO  (rapidly  changing  into  Fe2O3),  P2O5,  H2O  28  per 
cent.  Clino-Rh.,  but  commonly  in  bladed  and  fibrous  examples  of  a 
greenish-blue  or  deep  indigo-blue  colour ;  rarely  colourless,  and  then 
containing  FeO  only;  EL  2 ;  G  26-2-7.  Flexible  in  thin  pieces. 
BB  becomes  red,  and  fuses  into  a  magnetic  globule,  LUDLAMITE, 
from  Cornwall,  is  closely  related,  but  has  less  water  (17  per  cent.). 

STRENGITE  :  Fe'O3,  P2O5,  H2O  19-20  per  cent. ;  Rh.,  but  chiefly  in 
fibrous  mamillated  examples  of  a  bluish-red  or  pink  colour,  rarely 
colourless;  H  3-4;  G  2-9.  BB,  easily  fusible  into  a  magnetic* 
globule. 

CHILPRENITE:  MnO  10,  Fe203  29,  AK)3  14,  P2O5  29,  H2O  18. 
Rh. ;  H  4-5-5  ;  G  3-2-3 "3.  Yellowish-white,  yellow,  blackish-brown. 
BB,  intumesces,  and  forms  a  dark  magnetic  slag  or  semi-fused  mass. 

BERAUNITB:  Fe'O3,  P'O5,  H*O  16-5  per  cent.  In  radiated  and 
leafy  examples  of  a  red  or  red-brown  colour  and  yellow  streak ; 
H  2;  G  2-9-3;  BB,  fusible,  magnetic* 


166  BLOWPIPE    PRACTICE. 

HUREAULITE:  MnO  41,  FeO  8,  P2O5  39,  H2O  12.  Clino-Rh., 
mostly  tabular ;  also  coarse-fibrous,  &c.  H  3-5 ;  G  3*2 ;  yellowish- 
red,  red-brown,  more  rarely  violet  or  reddish-white.  BB,  easily 
fusible  into  a  dark,  feebly-magnetic  globule. 

HETEROSITE  :  FeO  (changing  into  Fe2O3),  MnO  (changing  into 
MnGa;,  P2O5,  H2O  4-4  per  cent.  Massive;  H  4-5-5;  G  3 '4-3-5  ; 
greenish  or  bluish-grey,  violet,  brown.  BB,  fusible,  magnetic. 

C2.— WITH   BORAX,  BB,  A  GLASS  COLOURED  BY   COPPER  OR  URANIUM  OXIDE- 
STREAK  LIGHT-GREEN  OR  YELLOW. 

f  Water-percentage  14-19. 

LIME.URANITE  (AUTUNITE)  :  CaO  6-10,  U2O3  62-75,  P2O5  15-47, 
IPO  15-68,  but  sometimes,  and  normally,  nearly  19  per  cent,  of 
water  present.  Tet.,  or  Rh.  with  marked  tetragonal  aspect,  mostly 
tabular  from  predominance  of  basal  plane,  and  thus  passing  into 
foliated  examples.  Yellow,  greenish-yellow  ;  H  1-2 ;  G  3-3*2  ; 
BB  intumesces  slightly,  and  fuses  into  a  dark  bead  with  crystalline 
surface.  In  nitric  acid  forms  a  yellow  solution.  URANOSPHO^RITE 
is  a  related  uranium  phosphate,  but  with  baryta  in  place  of  lime. 
Yellowish-green ;  G  3-5. 

COPPER-TJRANITE     (CflALKOLITE,    TORBERNITfi)  :     CuO    8'43,     TJ203 

61-19,  FO5  15-08,  H2O  15-30.  Tet.,  mostly  tabular,  passing  into 
foliated  micaceous  examples.  Emerald-green,  paler  in  the  streak, 
with  metallic-pearly  lustre;  H  2-2 -5 ;  G  3-5-3-6.  BB,  fusible  and 
reducible  to  metallic  copper.  Forms  in  nitric  acid  a  yellowish-green 
solution. 

CHALKOSIDERITE  :  CuO  (8-15),  Fe'O3,  A12O8,  P3O5,  H20  15  per 
cent.  In  small,  light-green,  anorthio  crystals.  G  3*1. 

ft  Water-percentage  8-11. 

TAGILITE:  'CuO  61-85,  P2O5  27-64,  H2O  10-51.  Clino-Rh.?  but 
mostly  fibrous,  mammillated,  &c. ;  emerald-green;  H  3;  G  4-4-1. 
BB,  fusible  and  reducible.* 

EHLITE  ;  CuO  67,  PW  24,  H2O  9.  Rh.  1  but  mostly  in  foliated 
and  bladed  examples,  with  pearly  lustre  on  cleavage  surface;  H  1-5-2; 
G  3-94-3.  Decrepitates  in  bulb-tube.  On  charcoal,  reduced.! 

•  The  reduced  copper-globule  is  surrounded  by  a  black  coating  of  unreduced  phosphate* 
With  carb.  soda,  perfect  reduction  ensues. 

t  The  re  U  oed  oappe^glohuje  is  surrounded  by  a  black  coating  of  unreduced  phosphate^ 
WiUi  ca.rU.  soda,  perfect  reduction,  ensues. 


MINERAL   TABLES  : — XVII.  167 

PHOSPHORCHALCITE  :  CuO  70-88,  P2O5  21-10,  H>0  8-02.  Clino- 
Rh.,  but  mostly  fibrous,  mammillated,  <fcc.  ;  green,  blackish-green; 
H  4-5-5;  G  4-1- 4-3;  decrepitates  and  blackens  on  ignition;  fuses 
to  a  dark  bead  with  crystallized  surface ;  on  charcoal,  reduced.* 
DIHYDRITE  is  closely  related,  but  consists  of  CuO  69,  P2O5  24*7, 
IFO  6-3. 

f  f  f  Water-percentage  under  4. 

LIBETHENITE  :  CuO  66'5,  PO5  29-7,  H20  3-8.  Rh.,  crystals  very 
small ;  dark-green,  blackish-green ;  H  4 ;  G  3'6-3'9.  Decrepitates 
and  blackens  in  bulb-tube.  In  forceps,  melts  to  a  dark  bead  with 
crystallized  surface.  On  charcoal,  forms  a  black  globule  surrounding 
reduced  copper. 

#%  Some  examples  of  Wavellite,  Peganite,  Fischerite,  and  Turquoise  (see 
under  C3,  below),  contain  a  small  amount  of  CuO,  and  thus  give  a  copper- 
reaction  with  borax. 

C3.— IN  POWDER,  COLOURED  BRIGHT-BLUE  BY  IGNITION  WITH 
COBALT-SOLUTION. 

f  Water-percentage  20-40. 

WAVELLITE:  A12O3  38-10,  P2O*  35-16,  H2O  26-47,  but  traces  of 
Fluorine  often  present.  Rh.  (crystals  mostly  small  and  indistinct), 
commonly  in  botryoidal  radiated-fibrous  examples  of  a  pale  green, 
greenish-white,  or  yellowish-white  colour;  H  3*5-4  ;  G  2-3-2-5.  BB, 
swells  up,  separates  into  fibres  and  becomes  opaque-white,  but  does 
not  fuse. 

FISCHERITE — PEGANITE — YARISCITE:  Hydrated  aluminous  phos- 
phates closely  related  to  Wavellite.  Rhombic  in  crystallization,  but 
commonly  in  radiated  fibrous  examples  of  a  green  or  white  colour. 
H  3-5;  G  about  2 -5.  BB,  like  Wavellite.  Planerite,  Striegisan, 
Richmondite,  Evansite  and  Zepharoviehite  are  probably  altered 
examples.  These  minerals  can  only  be  distinguished  by  accurate 
chemical  analysis.  Many  give  a  slight  copper-reaction.  The  per- 
centage of  water  is  as  follows  :  Variscite  23,  Peganite  24,  Wavellite 
26-5,  Zepharoviehite  27,  Fischerite  29,  Richmondite  35,  Evansite 
40-42. 

CALAITE  or  TURQUOISE  :  Al'O3  47,  P2O*  32-5,  H2O  20-5.  In  light- 
blue  and  bluish-green  amorphous  masses;  H  6;  G  2'6-2'8.  BB, 

*The  reduced  copper-globule  is  surrounded  by  &  black  coating  of  unreduced  phosphate. 
With  carb,  soda,  perfect  reduction  ensues. 


108  BLOWPIPE    PRACTICE, 

decrepitates,    and    often    blackens,    but   remains    unfused.      Many 
examples  shew  traces  of  copper. 

f  f  Water-percentage  under  13. 

LAZULITE  :  MgO,  FeO,  Al'0,  PO*,  H*O  (5-7  per  cent).  Clino- 
Rh.  (but  scarcely  differing  from  Rhombic  in  aspect  and  measure- 
ments). Blue,  bluish-white;  H  5-6;  G  3-3'2.  BB,  exfoliates  and 
crumbles,  but  does  not  fuse. 

BEELINITE — TBOLLEITE — AUGELJTE:  Hydrated  aluminous  phos- 
phates of  a  blue  or  greenish-blue  colour.  Water  percentage  :  4,  6, 
and  12 '5  respectively.  Obscurely  known  or  doubtful  species. 

C«.-IN  POWDER,  COLOURED  PALE-RED,  GREEN,    OK  DARK-GREY  BY  IGNITION 
WITH  COBALT-SOLUTION. 

f  With  Co-solution,  pale-red. 

LUNEBERGITE:  MgO,  P*O5,  B'O3,  H'O  (30-23  per  cent.).  In 
white,  fibrous  and  earthy  masses.  H  1-1-5  ;  G  2 -05.  Easily  fusible, 
with  green  coloration  of  the  flame-border.  With  sulphuric  acid  and 
alcohol,  gives  the  green  flame  characteristic  of  B2O3. 

STRUVITE  :  a  hydrous  phosphate  of  ammonia  and  magnesia.  Rh. 
(hemimorphic).  Colourless,  yellowish,  pale-brown  ;  H  1  -5-2  ;  G 
1-6- 1'8.  In  peat-bogs,  guano-deposits,  &c.  Evolves  ammoniacal 
fumes  on  ignition. 

f  f  With  Co-solution,  light-green. 
(BB,  on  charcoal  with  carb.  soda,  a  zinc  sublimate}. 

HOPEITE:  ZnO,  P2O5,  HO?  Rh. ;  greyish-white;  H  2'5-3;  G 
2*7-2 '8.  BB,  fusible  into  a  white  bead.  Some  examples  shew 
presence  of  cadmium. 

1 1  f  With  Co-solution,  dark-grey. 

BRUSHITE:  CaO  32-6, 1*0*41-3,11*0  26-1.  Clino-Rh.;  colourless, 
yellowish;  H  1*5;  G  2*2.  Metabrushite  and  Isoclase  are  related 
products.  In  all,  the  presence  of  C»O  is  readily  determined  by  the 
spectroscope, 

OHURCHITE:  CaO,  CeO,  DiO,  P'O5,  H'2O  (15  per  centA  Clino- 
Rh.  (?)  radiated.  Greyish-white,  pale-red ;  H2-5-3;  G  o'L  Imper- 
fectly known, 


MINERAL  TABLES  1 — XVII.  169 


NOTE  TO  TABLE  XVII. 

This  Table  is  represented  by  Phosphates,  or  by  Phosphates  combined  with 
Fluorides  or  Chlorides.  Its  more  important  species  may  be  referred  broadly 
to  the  following  groups  :  (1)  Apatites  ;  (2)  Triplites;  (3)  Alumina  Phosphates; 
(4)  Iron  and  Copper  Phosphates  ;  (5)  Uranium  Phosphates. 

The  Apatite  group  is  characterized  by  its  Hexagonal  crystallization,  and  by 
the  common  formula  3  (3  RO,  P2O5)  +  R  (Fl,  Cl)2.  It  is  represented  by 
Apatite  and  Pyromorphite,  and  also  by  the  related  arseniate  and  vanadiate, 
Mimetesite  and  Vanadinite,  the  latter  described,  in  a  technical  work  of  this 
kind,  under  other  Tables.  Apatite,  often  known  commercially  as  "Phosphate," 
is  largely  employed  in  the  manufacture  of  Superphosphate  of  lime,  so  exten- 
sively used  as  a  fertilizer.  It  commonly  presents  itself  in  cleavable  masses  or 
hexagonal  prisms  of  a  light  or  deep  green  colour,  but  is  frequently  chocolate- 
brown,  red,  or  almost  colourless.  Green  and  reddish  tints  are  often  inter- 
mingled. The  edges  of  the  crystals  are  frequently  rounded.  The  more 
common  crystals  are  simple  six-sided  prisms  with  large  basal  plane,  or  these 
with  a  slight  pyramidal  replacement  on  the  basal  edges  ;  but  Canadian  crystals 
(when  unbroken)  shew  complete  pyramidal  terminations,  without  any  basal 
plane.  As  regards  composition,  Apatite  includes  two  leading  varieties  : 
fluoride  of  calcium  being  present  in  one,  and  chloride  and  fluoride  in  the  other. 
Both  are  readily  dissolved,  in  powder,  by  nitric  acid,  and  the  diluted  solution 
yields  a  yellow  precipitate  with  amm.  molybdate,  especially  on  being  warmed. 
Very  carefully  neutralized  by  ammonia,  it  gives  also  a  yellow  precipitate  with 
nitrate  of  silver.  Heated  with  a  few  drops  of  sulphuric  acid,  both  varieties, 
as  a  rule,  give  a  marked  fluorine-reaction,  the  evolved  fumes  exerting  a  strongly 
corrosive  action  on  glass.  Before  the  blowpipe,  Apatite  is  infusible,  or  is 
rounded  only  on  the  thinnest  edges.  The  powder  moistened  with  sulphuric 
acid  tinges  the  flame  border  pale  green,  thus  shewing  the  presence  of  phosphoric 
acid  ;  and  in  the  spectroscope  the  green  and  red  Ca-lines  are  readily  produced, 
but  this  latter  reaction  is  best  obtained  by  moistening  the  powder  with  hydro- 
chloric acid. 

Pyromorphite  is  essentially  a  chloro-phosphate  of  lead.  It  is  commonly  in 
groups  of  small  crystals  of  a  dark  or  light  green,  brown,  or  grey  colour.  The 
so-called  yellow  varieties  are  mostly  Mimetesite,  or  mixtures,  at  least,  of 
phosphate  and  arseniate.  The  crystals  are  chiefly  simple  six-sided  prisms, 
frequently  barrel-shaped  by  curvature.  The  name  Pyromorphite  refers  to  the 
peculiar  blowpipe  reaction  presented  by  the  mineral.  Per  se  (if  free  from 
arseniate),  it  is  not  reduced,  but  melts  easily  into  a  light-yellowish  or  greyish 
bead  which  crystallizes  over  the  surface  on  cooling.  Pyromorphite  is  easily 
soluble  in  nitric  acid, 

The  group  of  Triplites  is  principally  represented  by  Triplite,  Triphyline, 
and  Amblygonite,  practically  anhydrous  phosphates  or  fluo- phosphates  of  easy 
fusibility.  Triplite  is  mostly  in  dark-brown  oleavable  masses,  giving  marked 
reactions  of  manganese  and  fluorine.  Triphyline  is  also  in  cleavable  masses, 
but  of  a  light  colour,  essentially  pearl-grey,  greyish-blue,  or  greyish-green. 


170  BLOWPIPE   PRACTICE. 

It  gives  no  marked  fluorine  reaction,  but  if  moistened  with  hydrochloric  acid, 
or  mixed  in  powder  with  chloride  of  barium,  it  shews  in  the  spectroscope  the 
crimson  Li-line  very  prominently.  Amblygonite  (see  the  Table)  is  a  rare 
mineral.  It  gives  both  Fl  and  Li  reactions. 

The  group  of  hydrated  alumina-phosphates  is  chiefly  represented  by  Wavellite 
and  Kalaite,  the  latter  more  generally  known  as  the  Turquoise.  Wavellite 
occurs  rarely  in  distinct  crystals,  but  is  generally  in  botryoidal  and  radiated- 
fibrous  examples  of  a  green  or  greenish-white  colour,  and  is  found  more 
especially  in.  argillaceous  slates.  It  is  soluble  in  acids,  and  also  in  a  strong 
solution  of  caustic  potash.  Before  the  blowpipe,  it  exfoliates,  becomes  opaque 
white,  and  tinges  the  flame  pale-green,  but  does  not  fuse.  Most  specimens 
give  with  sulphuric  acid  a  slight  fluorine-reaction.  When  pure,  the  water- 
percentage  =  26£.  Kalaite  or  Turquoise  occurs  chiefly  in  small  nodidar  or 
flattened  masses  of  a  bright  blue,  bluish -white,  or  bluish-green  colour. 
These  scratch  glass  slightly  ;  but  many  so-called  turquoises  are  merely  pieces 
of  fossil  bone  coloured  by  copper  oxide.  In  these,  the  hardness  rarely  exceeds 
3  ;  and  they  give  off  in  most  cases  a  marked  ammoniacal  odour  on  ignition. 
In  the  true  turquoise  the  water  percentage  =  20£. 

Vivianite,  Phosphorchalcite,  and  Libethenite  are  the  chief  representatives 
of  the  group  of  Iron  and  Copper  Phosphates,  characterized  by  their  peculiar 
blue  and  green  colours.  Many  of  these  are  isoniorphous  with  arseniates  of 
corresponding  formulae.  Vivianite,  normally,  is  colourless,  but  the  FeO,  pre- 
sent in  it,  becomes  rapidly  converted  into  Fe^O3,  and  the  mineral  assumes  a 
blue  or  bluish-green  colour,  with  pale  blue  or  greenish  streak.  It  is  commonly 
in  flat-fibrous  or  bladed  masses.  It  reddens  on  ignition,  and  inelts  into  a  dark- 
grey  magnetic  bead.  Easily  soluble  in  acids.  Blackened  in  a  hot  solution  of 
caustic  potash.  Water  percentage  =  28.  Phosphorchalcite  occurs  commonly 
in  groups  of  small  clino-rhombic  crystals  and  in  fibrous  examples  of  a  blackish- 
green  or  emerald-green  colour,  paler  in  the  streak.  It  blackens  in  the  bulb- 
tube,  and  evolves  about  8  per  cent,  water.  Before  the  blowpipe  it  commonly 
decrepitates,  and  then  melts  into  a  black  globule  containing  in  its  centre 
reduced  copper.  If  the  dark  globule  be  fused  with  a  small  cutting  of  metallic 
lead  it  crystallizes  on  cooling.  Libethenite  closely  resembles  it  in  general 
characters  and  in  its  blowpipe  reactions,  but  is  rhombic  in  crystallization^  and 
yields  only  3*77  per  cent,  water.  Its  colour  also,  as  a  rule,  is  much  less  bright. 
It  is  isomorphous  with  the  arseniate  Olivenite. 

The  group  of  Uranium  Phosphates  includes  only  the  Autunite  or  Lime- 
Uranite,  and  the  Chalkolite  (Torbernite)  or  Copper- Uranite.  The  lime-uranite 
is  distinguished  by  its  pale  yellow  or  yellowish-green  tint,  and  the  copper- 
uranite  by  its  splendid  emerald-green  colour.  Both  occur  commonly  in  small 
lamellar  or  micaceous  examples,  and  in  groups  of  small  tabular  crystals. 
These  latter  are  rhombic  in  the  lime-uranite  (but  with  strongly  tetragonal 
aspect),  and  tetragonal  in  copper-uranite.  Both  species  fuse  more  or  less 
easily,  and  the  latter  gives  reduced  copper.  Both  species  dissolve  readily  in 
nitric  acid,  and  are  decomposed  by  caustic  potash  with  abstraction  of  their 
phosphoric  acid.  Water  percentage  15-16. 


[171] 


TABLE    XVIII. 

[Lustre  non-metallic.     Easily  dissolved  BB  by  borax  or  phosphor- salt.     Green 
coloration  of  flame  by  treatment  with  sulphuric  acid  and  alcohol.] 

A-— Anhydrous  Species.    No  water  evolved  (or  merely 
traces)  by  ignition  in  bulb-tube- 

BORACITE  :  MgO  27,  B2O3  62-5,  MgCl2  10-5.  Reg.  (see  Note  at 
end  of  Table) ;  H  7 ;  G  2*9-3 ;  colourless,  pale  greenish,  reddish, 
<fec. ;  streak  white.  Mostly  in  small  crystals  imbedded  in  anhydrite 
or  gypsum.  BB  fusible  with  intumescence,  tinging  the  flame  green. 
With  CuO  and  phosphor-salt,  gives  chlorine-reaction.  Slowly  dis- 
solved by  hydrochloric  acid.  RHODIZITE  (in  small  crystals  on  some 
Siberian  tourmalines)  is  regarded  as  a  lime  boracite.  H  8 ;  G  3'3. 

LUDWIGITE:  MgO,  FeO,  Fe2O3,  B2O3.  In  fibrous  or  prismatic 
masses  of  a  dark-green  or  greenish-indigo  colour ;  H  5 ;  G  4 ;  BB, 
fusible  slowly  into  a  dark  magnetic  bead.  The  only  examples 
hitherto  recognized  occur  with  magnetic  iron  ore  in  the  Bannat. 

B.— Hydrous  Species,  yielding  water  on  ignition. 

Bl.— DISTINCTLY  SOLUBLE  AND  SAPID. 

SASSOLINE  (Boracic  Acid) :  B2O3  56-45,  H20  43-55.  Clino-Rh.  or 
Anorthic  (?),  but  essentially  in  small  pearly-white  scales  and  tabular 
examples,  sometimes  stained  by  ferruginous  matter.  H  1 ;  G  1  '4-1  '5 ; 
bitter-acid  taste,  soapy  to  the  touch.  BB  tinges  the  flame  green,  and 
melts  with  intumescence  into  a  hard  clear  glass. 

LARDERELLITE  (Hydrated  Borate  of  Ammonia) :  In  small  rhombic 
or  rectangular  plates  and  scales  of  a  white  colour.  Scarcely  soluble, 
except  in  hot  water,  and  thus  almost  tasteless.  See  below,  under  B2." 

BORAX  or  TINKAL  :  Na2O  16-2,  B2O3  36-7,  H2O  47'1.  Clino-Rh. ; 
H  1-5-2-5;  G  1-7-1-8;  colourless,  or  stained  brown,  yellowish,  &c., 
by  impurities.  Taste,  slightly  alcaline.  BB,  intumesces  and  melts 
easily,  but  (as  regards  natural  or  crude  varieties)  the  glass  is  dark  or 
more  or  less  coloured.  Moistened  with  sulphuric  acid,  or  with 
glycerine,  it  tinges  the  flame  green. 

B3.— PRACTICALLY  INSOLUBLE  AND  WITHOUT  TASTE;  OR  DECOMPOSED  BY 
BOILING  WATER  ONLY. 

f  No  marked  Mn  or  Fe  reaction. 

STASSFURTITE  (Massive  and  slightly  altered  BORACITE  ?)  :  In  fine- 
granular  or  fibrous  masses  of  a  white  or  yellowish-white  co  our. 


172  BLOWPIPE    PRACTICE. 

Yields  0-5-1  per  cent,  water  on  ignition :  composition  otherwise  as 
in  Boracite.  H  4-5-5  ;  G  2-9-3-0.  Readily  fusible. 

SZAILBELYITE  :  MgO,  B*O*,  H'O  (7-12-5  per  cent.).  In  small 
globular  masses  of  radiated-fibrous  structure  and  white  colour;  H 
3-5  ;  G  2-7.  Easily  fusible. 

HYDROBORACITE  :  CaO,  MgO,  B2O8,  H2O  (26  per  cent.).  In 
crystalline,  radiated-fibrous  or  leafy  masses  of  a  white  or  pale  reddish 
tint.  H  2 ;  G  1  -9-2.  Very  easily  fusible.  Shews  red  and  green 
Ca-lines  in  spectroscope  if  moistened  with  HC  acid. 

BOROCALCITE  :  CaO,  B2O3,  H*O  (35-5  per  cent).  Clino-Rh.  ? 
Mostly  in  snow-white  acicular  crystals  and  incrustations.  Very 
easily  fusible.  BECHILITE  is  closely  related,  but  yields  less  water 
(2)75  per  cent.).  Both  shew  Ca-lines  in  spectroscope  when 
moistened  with  HC  acid.  PRICEITE,  a  milk-white  chalky  borate  of 
lime,  with  20*3  per  cent,  water,  from  Oregon,  is  probably  identical, 
the  amount  of  water  in  these  earthy  borates  being  very  inconstant. 

ULEXITE  (BORONATROCALCITE)  :  Na'O  6-80,  CaO  12-21,  B2O3  45-66, 
H2O  35 '33.  In  white,  mainillated  and  fibrous  masses.  G  1*8.  Very 
easily  fusible  with  yellow  coloration  of  the  flame.  Decomposed,  in 
powder,  by  boiling  water.  TINKALZITE  and  CRYPTOMORPHITE  are 
closely  related  substances. 

LARDERELLITE  :  Ammonia  127,  B2O*  68-6,  H20  187.  In  white 
shining  scales  or  small  crystalline  plates  resembling  Sassoline.  Solu- 
ble in  hot  water.  Yielding  ammoniacal  fumes  on  ignition.  Fusible 
with  strong  intumescence. 

1 1  BE,  marked  reaction  of  Iron  or  Manganese. 

SUSSEXITE  :  MnO,  MgO,  B2O3,  H2O  (9  per  cent.).  In  white,  or 
pale-reddish,  silky-fibrous  masses.  H  25-3;  G  3'42.  Very  easily 
fusible,  with  green  flame-coloration. 

LAGONITE:  F2O3,  B2OS,  H2O  (1273  per  cent).  In  yellow,  ochreous 
masses  from  the  boracic-acjd  lagoons  of  Tuscany. 


NOTE  TO  TABLE  XVIII, 

This  Table,  apart  from  Boraoic  Acid,  is  composed  exclusively  of  Borates, 
distinguished  readily  from  other  compounds  by  the  peculiar  yellowish-green 
coloration  which  they  impart  (when  moistened  with  sulphuric  acid)  to  the 
flame  of  alcohol.  Many  of  these  minerals  are  still  imperfectly  known,  and  are 


MINERAL    TABLES  : — XVIII.  173 

apparently  of  somewhat  inconstant  composition,  more  especially  as  regards  the 
hydrous  species.  Boracite  and  Tinkal  (crude  Borax)  are  the  principal  repre- 
sentatives of  the  Table. 

Boracite  [2  (MgO,  B'O3)  +  Mg  Cl2]  occurs  essentially  in  small  hemihedrally- 
modified  crystals  of  the  Regular  System,  remarkable  for  their  high  degree  of 
hardness,  which  equals  that  of  ordinary  quartz.  Hence  they  scratch  glass 
very  distinctly.  They  are  generally  colourless,  but  sometimes  present  a  pale 
grey,  greenish  or  yellowish  tint,  and  are  always  assoriated  with  anhydrite, 
gypsum,  or  rock  salt.  The  most  simple  consist  of  the  cube  truncated  on  the 
alternate  angles,  and  thus  presenting  a  combination  of  cube  and  tetrahedron. 
Very  commonly  the  cube-edges  are  also  truncated  by  the  planes  of  the  rhombic 
dodecahedron  ;  and  the  latter  form  predominates  in  some  crystals.  As  in  most 
other  hemihedrally-modified  minerals,  Boracite  is  pyro-electric.  The  substance 
known  (from  its  locality)  as  Stassfurtite  appears  to  possess  essentially  the 
same  composition,  except  that  it  yields  a  small  amount  of  water  on  ignition. 
This  substance  is  thus  commonly  regarded  as  massive  Boracite,  but  its  hardness 
is  comparatively  low,  usually  under  5.  It  occurs  mostly  in  granular  or  sub- 
fibrous  masses  of  a  chalky- white  colour.  Tinkal  or  crude  Borax  (Na20,  2B208 
-t-  10  H20)  is  a  product  of  certain  salt  lakes,  and  is  mostly  in  the  form  of  small 
granular  or  crystalline  masses  of  a  greyish  or  brownish-white  colour.  Mois- 
tened with  sulphuric  acid,  or  simply  with  glycerine,  it  imparts  a  distinct  green 
coloration  to  the  flame.  Per  se,  it  colours  the  flame  intensely  yellow,  and 
melts  with  great  intumescence  into  a  more  or  less  clear  bead.  In  the  bulb-tube 
it  evolves  47 '2  per  cent,  water.  Its  crystallization  is  Clino-Rhombic,  and  the 
ordinary  borax  crystals  have  a  remarkable  resemblance,  even  in  their  angle 
values,  to  those  of  Augite. 


[174] 


TABLE  XIX. 

[  Lustre  non-metallic.  Easily  dissolved,  BB,  by  borax  or  phosphor-salt.  Giving 
with  the  latter  reagent  and  CuO  an  intensely  azure-blue  or  green  flame 
(01.,  Br.,  or  I  reaction)]. 

A.— Soluble  in  Water.    Sapid. 

AI.-NO  WATER  <OR  MERELY  TRACES)  IN  BULB-TUBE. 
f  Entirely  dissolved  BB  by  carb.  soda. 

ROCK  SALT  (Halite) :  Sodium  39-31,  Chlorine  60'69.  Reg.,  with 
cubical  cleavage;  H  2  ;  G  2-1-2-2;  colourless,  white,  grey,  greenish, 
red,  violet,  &c.  ;  streak  white ;  taste,  strongly  saline,  sometimes 
bitterish  from  presence  of  chloride  of  magnesium  and  other  im- 
purities. BB,  generally  decrepitates,  colours  the  flame  strongly 
yellow,  melts,  and  in  prolonged  heat  sublimes. 

SYLVINE  :  K  52-35,  Cl  47-65,  but  generally  contains  NaCl.  Reg. ; 
H  2;  G  1-9-2;  colourless,  greyish,  reddish,  &c. ;  taste,  like  that  of 
rock  salt.  BB,  easily  fusible,  colouring  the  flame  violet  if  pure.  In 
spectroscope,  even  if  impure  from  NaCl,  &c.,  it  shews  the  red  K-line 
very  distinctly  (See  Part  I.,  p.  58-59). 

SAL  AMMONIAC  (Chloride  of  Ammonium)  :  Reg.,  but  commonly  in 
crusts  and  earthy  coatings;  H  PO-2  ;  G  1'5-1'G;  white,  brownish, 
yellowish.  Taste,  pungent,  saline.  Entirely  volatilizable  without 
fusion.  Ignited  with  caustic  potash,  gives  off  ammoniacal  fumes. 

f  f  BB  with  carb.  soda  only  partially  attacked,  an  undissolved  mass 

remaining. 

CHLOROCALCITE  (Chloride  of  Calcium).  In  white  crusts  on  some 
Vesuvian  lavas,  often  associated  with  thin  scales  and  crystals  of  Iron 
Glance.  Shews  red  and  green  Ca-lines  in  spectroscope  very  distinctly. 

TACHHYDRITE:  CaCP  21,  MgCl2  37,  H2O  42.  In  rounded  cleav- 
able  masses  of  a  yellow  colour  assoriated  with  Carnallite,  Anhydrite, 
&c.  Very  deliquescent.  Easily  fusible.  Ca-lines  in  spectroscope. 

CARNALLITE  KC1  26-8,  Mg  Cl2  34-2,  H2O  39.  Rh.,  with  pseudo- 
hexa<*onal  aspect,  but  commonly  in  fine  granular  examples  of  a  white 
colour,  or  sometimes  red  from  intermixed  Fe2O3  or  scales  of  Iron 
Glance.  Deliquescent.  Easily  fusible.  Shews  red  K-line  in  spectro- 
scope, together  with  Na-line,  part  of  the  KC1  being  generally  replaced 


MINERAL   TABLES: — XIX.  175 

by  NaCl.     Found  essentially  in  salt  deposits.     Some  examples  are 
said  to  contain  traces  of  Thallium,  also  Caesium  and  Rubidium. 

KREMERSITE  :  Am,  K,  Fe,  01,  H*O.  In  small  octahedrons,  of  a 
red  colour,  on  some  Vesuvian  lavas.  Easily  soluble.  Deliquescent. 

B.— Yielding  reduced  metal,  BB,  with  carb.  soda  on  charcoal. 

f  BB  a  silver  globule. 

KERARQYRITE  (Horn  Silver  Ore) :  Ag  75'3,  Cl  24-7.  Reg.,  but 
commonly  in  granular  masses  and  coatings  of  a  grey,  greenish,  or 
violet-brown  colour,  and  waxy  aspect.  H  1-1  -5  ;  G  5*6 ;  very  sectile. 
BB  melts  with  bubbling,  and  on  charcoal  is  easily  reduced. 

BROMARGYRITE  :  Ag  57*4,  Br  42*6.  Yellow,  yellowish-green.  Sec- 
tile,  and  otherwise  like  Kerargyrite,  but  giving  green  and  blue  flame 
by  fusion  with  phosphor-salt  and  CuO.  Fused  with  bisulphate  of 
potash  in  a  small  test-tube,  it  forms  a  blood-red  globule  which  becomes 
yellow  when  cold,  and  turns  green  on  exposure  to  sunlight.  Chloride 
of  silver  (Kerargyrite)  under  this  treatment,  gives  an  orange-red  bead 
which  becomes  yellowish-white  on  cooling,  and  dark-grey  on  exposure. 
Iodide  of  silver  forms  an  amethyst-red  globule  which  turns  dingy- 
yellow  on  cooling,  and  does  not  undergo  further  change  on  exposure. 
See  Appendix  to  Part  I,  page  90.  Microbromite,  EmboHte,  and  Mega- 
bromite  are  isomorphous  chloro-bromides,  containing,  respectively, 
69*8,  66  9,  and  64-2  per  cent,  silver.  These  (and  intermediate  vari- 
eties) resemble  Kerargyrite  in  general  characters. 

IODARGYRITE  ;  Ag  46,  I  54,  yellow,  sectile,  like  Kerargyrite  in 
general  characters,  but  giving  emerald-green  flame  with  phosphor-salt 
and  CuO.  Fused  with  bisulphate  of  potash  in  closed  tube,  it  forms 
a  dark  amethystine  globule,  which  turns  greyish  yellow  on  cooling. 
Slight  fumes  of  Iodine  are  also  evolved.  Torconalite  is  a  rare  com- 
pound of  Ag  I  and  Hg  I.  It  yields  a  sublimate  of  mercury  by  fusion 
with  reducing  agents  (dry  carb.  soda,  neutral  ox.  potash,  &c.)  in 
closed  tube. 

t  f  BB,  copper  globule  and  reactions. 

NANTOKITE  :  Cu  64,  Cl  36.  White  or  colourless,  normally,  but 
often  greenish  externally  from  partial  conversion  into  the  oxy-chloride 
Atacamite.  In  small  granular  and  disseminated  masses  with  cubical 
cleavage.  H  2  ;  G  3*9.  Fusible,  and  in  chief  part  volatilizable,  BB, 
colouring  the  flame  intensely  blue.  Soluble  in  ammonia  and  in  acids. 


176  BLOWPIPE   PRACTICE. 

ATACAMITE:  Cu6l2  CuO,  H20  (12  J  —  22J  per  cent).  Bh.,  but 
mostly  in  small  grains  of  a  deep-green  colour.  H  3-3*5  ;  G  3-7-3-77. 
Fusible  and  reducible,  colouring  the  flame  blue.  Soluble  in  ammonia 
and  acids.  Atelite  (from  Vesuvius)  and  Tallingite  (from  Cornwall) 
are  closely  related  compounds,  the  latter  blue  in  colour.  Atlasite 
(from  Chili)  is  apparently  Atacamite  converted  in  chief  part  into 
green  carbonate. 

PERCYLITE  :  CuCP,  Pb  Cl2,  CuO,  PbO,  H20.  Reg  (crystals  very 
small) ;  sky-blue.  Fusible  and  reducible,  with  strong  coloration  of 
flame  and  lead  sublimate  on  charcoal.  Hitherto  only  found  with 
alluvial  gold  in  Mexico. 

1 1 1  Pb  or  Bi  globule  and   yellow  coating  BB  with  carb.   soda  on 

charcoal. 

COTUNNITE  :  Pb  74*5,  Cl  25'5.  Eh,  (crystals  acicular)  ;  H  1-5-2  ; 
G  5 '24  ;  white,  with  adamantine  lustre.  Fusible  and  volatilizable. 

MATLOCKITE  :  PbCl2  55-5,  PbO  44-5.  Tet.  Yellowish  or  greenish  ; 
H  2-5  ;  G  7'2.  BB,  decrepitates  and  fuses.  With  carb.  soda,- easily 
reducible.  Very  rare.  Hitherto  only  found  in  Derbyshire  with  lead 
carbonate  and  flu  or  spar. 

MENDIPITE  :  PbCP  38'4  PbO  61 '6,  but  commonly  in  part  altered 
to  carbonate.  In  small  sub-columnar  or  fibroas  masses;  Rh.?; 
H2-5-3;  G  7-0-7-1.  BB  decrepitates,  fuses,  and  on  charcoal  is 
reduced.  A  rare  mineral. 

PHOSGENiTE(Kerasine;  Corneous  lead  ore) :  PbCl251,  PbO,  CO2  49. 
Tet.;  yellowish-white,  yellow,  greenish,  grey;  H  2-5-3;  G  6-0-6-3. 
Easily  fusible  into  a  yellowish  bead  with  somewhat  crystalline  surface. 
With  carb.  soda,  lead  globules  and  yellow  sublimate.  In  acids,  soluble 
with  effervescence.  Very  rare.  Schwartzembergite  (from  the  Atacama 
Desert)  is  a  related  compound  containing  Iodide  of  lead.  Colour, 
yellow. 

DAUBREITE  :  BiCP  22-5,  Bi2O8  72-6,  H2O  3-8,  with  small  amount 
of  Fe2O3,  &o.  From  Bolivia.  Characters  undescribed. 

C.—No  reduced  metal  BB  on  charcoal,  but  mercurial  subli- 
mate with  carb.  soda  in  closed  tube. 

CALOMEL:  Hg  85,  Cl  15.  Tet.;  yellowish-white,  grey;  H  1-2; 
very  sectile ;  G  6-4-7  ;  BB  entirely  vol.  Blackens  in  caustic  potash  ; 
soluble  in  nitro-hydrochloric  acid,  bnt  not  in  nitric  acid  alone. 

COCCINITE  (?) :  Hg  I2.  Scarlet-red ;  Tetragonal.  Doubtful  as  a 
naturally-occurring  species. 


MINERAL    TABLES: XIX.  177 


NOTE  ON  TABLE  XIX. 

This  Table  consists  entirely  of  Chlorides  and  Oxy-Chlorides.  Other  chlorine 
compounds  combined  with  phosphates,  &c.,  will  be  found  in  preceding  Tables. 
The  only  important  species,  or  those  of  tolerably  frequent  occurence,  belonging 
to  the  present  Table,  consist  of  Rock  Salt,  Kerargyrite  or  Corneous  Silver  Ore, 
and  Atacamite. 

Rock  Salt  or  Chloride  of  Sodium  is  widely  distributed  in  the  form  of  beds, 
in  strata  of  various  geological  periods,  and,  in  solution,  in  sea-water  and 
numerous  mineral  springs.  It  occurs  also  as  a  product  of  sublimation  in  many 
volcanic  regions.  Normally,  it  is  colourless  and  transparent ;  but  is  very 
generally  of  a  red,  greenish,  grey,  violet  or  other  colour,  from  intermixed 
impurities.  Its  crystals  belong  to  the  Regular  System,  and  consist  chiefly  of 
simple  cubes,  or  of  aggregations  of  small  cubes  presenting  a  hopper-shaped 
aspect.  Other  forms  (the  octahedron,  &c.),  are  comparatively  rare.  The 
cleavage  is  cubical,  and  strongly  marked.  Lamellar,  granular,  and  sub-fibrous 
examples  are  also  abundant.  These  are  very  frequently  associated  with 
gypsum  and  gypsiferous  clay.  Although  normally  anhydrous,  rock  salt  (more 
especially  in  its  less  pure  varieties)  absorbs  moisture  from  the  atmosphere,  and 
runs  gradually  into  deliquescence.  It  dissolves  in  somewhat  less  than  3  parts 
of  water,  and  it  possesses  the  peculiarity  of  being  about  equally  soluble  in  hot 
and  cold  water.  Most  examples  decrepitate  very  strcfngly  on  ignition.  From 
other  chlorides  it  is  readily  distinguished  by  its  saline  taste  and  cubical 
crystallization  and  cleavage,  combined  with  its  intensely  yellow  flame-color- 
ation. 

Kerargyrite,  often  known  as  "Horn  Silver"  or  "Corneous  Silver  Ore,"  is 
readily  distinguished  by  the  large  globule  of  silver  obtained  from  it  by  the 
blowpipe,  and  by  its  waxy  aspect,  sectility,  and  shining  streak.  It  gives  also 
reduced  silver  if  moistened  and  placed  in  contact  with  a  piece  of  zinc.  It 
occurs  mostly  in  compact  masses  or  thin  layers  of  a  pearl-grey,  greenish  or 
blueish  colour,  turning  brown  on  exposure.  Unattacked  by  nitric  acid,  it 
dissolves  more  or  less  readily  in  ammonia. 

Atacamite  is  a  hydrated  compound  of  chloride  and  oxide  of  copper,  but  of 
somewhat  unstable  composition.  In  some  examples  the  water  equals  12-13  per 
cent. ,  and  in  others  it  is  as  high  as  22£  per  cent.  The  mineral  by  its  green  colour 
and  general  aspect  resembles  certain  cupreous  arseniates  and  phosphates,  but 
from  these  it  is  distinguished  by  the  azure-blue  coloration  which  it  commu- 
nicates to  the  blowpipe  flame,  as  well  as  by  the  precipitate  formed  in  its  nitric 
acid  solution  by  nitrate  of  silver.  As  seen  in  mineral  collections,  it  is  generally 
in  the  form  of  a  blackish -green  or  deep  emerald-green  sand.  Its  crystals  are 
small,  vertically- striated  prisms,  and  rectangular  octahedrons,  of  the  Rhombic 
System.  V :  V  =  112°  18'.  Cleavage  brachydiagonal. 

13 


[178] 


TABLE  XX. 

[Lustre  non-metallic.    Readily  soluble  BB  in  borax  or  phosphor- salt.    Wanned, 
in  powder,  with  sulphuric  acid,  evolve  glass-corroding  fumes.  ] 

A.— Fusible. 

t  Anhydrous,  or  yielding  merely  traces  of  moisture  on  ignition  in 

bulb-tube. 

FLUOR  SPAR  (Fluorite)  :  Ca  51-3,  F  48-7.  Reg.,  essentially  cubi- 
cal (see  Note  at  end  of  Table),  cleavage  octahedral;  H  4;  G  3-1-3-2; 
colourless,  violet,  yellow,  pale-green,  deep  bluish-green,  rose-red,  &c., 
with  white  streak.  In  most  cases  phosphorescent  when  heated.  BB, 
generally  decrepitates,  fuses  into  a  white  enamel,  which  tinges  the 
flame-border  distinctly  red,  and  reacts  alkaline,  after  prolonged 
ignition.  Ratofkite  is  a  mixture  of  fluor  spar  and  marl,  of  a  dull 
greyish-blue  colour. 

CRYOLITE  :  Na  32-8,  Al  13,  F  54-2.  Anorthic,  but  mostly  in 
lamellar  masses  with  nearly  rectangular  cleavage;  H  2*5-3  ;  G  2-9-3-0; 
white,  or  sometimes  slightly  yello wis  h  or  reddish ;  streak  white ; 
brittle.  Melts  in  candle-flame  into  a  white  enamel.  BB  on  charcoal, 
leaves  a  white  crust  which  becomes  blue  on  cooling  after  ignition 
with  cobalt  solution.  Soluble  in  boiling  solution  of  caustic  potash. 
Shews  strong  Na-line  in  spectroscope.  Chiolite  (Tetragonal),  Nip- 
holite,  Arksutite,  and  Fluellite,  are  related  compounds  of  similar 
aspect.  In  Arksutite  part  of  the  Na  is  replaced  by  Ca. 

SELLAITE:  Mg  38-7,  F  61-3.  Tet.;  colourless.  H  5;'G  2-97. 
Easily  fusible  into  a  white  enamel.  Becomes  pale-red  by  ignition 
with  cobalt  solution.  Very  rare.  Accompanies  anhydrite  at  the 
Gerbulaz  glacier  in  Savoy. 

LEUCOPHANE  :  CaO,  BeO,  SiO2,  NaF.  Rh.,  but  commonly  lK 
lamellar,  cleavable  masses.  H  3*5-4,  G  2 -9-3.  Greenish-grey, 
yellow.  Phosphorescent  when  heated  or  broken.  BB,  very  easily 
fusible.  MELINOPHANE  (Meliphanite)  is  a  closely  related  species  of 
a  yellow  colour,  but  Tetragonal  (?)  in  crystallization. 

t  f  Yielding  water  by  ignition  in  bulb-tube. 

PACHNOLITE  :  Na  10-35,  Ca  17-99,  Al  12-28,  F  51-28,  H2O  8-10. 
Clino-Rh.  (?).  In  minute  twin-crystals  in  cavities  of  Cryolite. 
Colourless,  strongly  shining.  BB,  crumbles  and  fuses  into  a  white 


MINERAL    TABLES  : XX.  179 

enamel.  In  bulb-tube  falls  into  powder  and  yields  8  per  cent,  water. 
In  spectroscope  shews  Na-line,  and  green  and  red  Ca-lines.  Thom- 
senolite  is  closely  related  or  identical. 

PROSOPITE  :  Ca,  Al,  Si,  F,  H20.  Anorthic;  colourless;  H  4-4'5; 
G  2 -9.  Often  earthy  from  decomposition.  Sometimes  altered  into 
fluor  spar.  An  imperfectly  known  species  accompanying  Iron  Glance 
at  Altenberg,  Saxony.  When  transparent  and  crystalline,  yields 
14P84  per  cent  water. 

B— Infusible. 

FLUOCERITE  :  Ce,  F. ;  Hex.  (crystals,  small,  tabular),  but  mostly  in 
granular  examples  of  a  pale-red  or  yellowish  colour.  H  4-5  ;  G  4*7. 
Whitens  or  becomes  yellow  on  ignition.  BB,  infusible.  Hydro- 
Huocerite  is  closely  related  (if  not  an  altered  fluocerite)  but  yields  on 
ignition  about  5  per  cent,  water. 

YTTROCERITE  :  Ca,  Ce,  Y,  La,  Di,  Er,  F,  H2O.  In  crystalline- 
granular  masses  of  a  light  greyish- violet  or  blue-grey  colour,  with 
imperfect  (tetragonal)  cleavage.  BB,  infusible. 

PARISITE;  HARMATITE:  Fluorides  combined  with  carbonates;  hence 
effervescing  in  acids.  See  Table  XIII. 


NOTE  ON  TABLE  XX. 

This  Table  consists  essentially  of  Fluorides.  Other  Fluor-compounds  com- 
bined with  phosphates  (Apatite,  Triplite,  &c.)  will  be  found  in  Table  XVII. 
Fluo-silicates  (apart  from  Leucophane,  placed  here  on  account  of  its  ready 
solution,  BB,  in  phosphor-salt  and  borax)  belong  to  one  of  the  succeeding 
Tables:  XXIV-XXVlt 

Fluor  Spar  is  the  only  commonly-occurring  or  generally  distributed  mineral 
belonging  to  the  present  Table.  It  occurs  very  commonly  with  ores  of  lead, 
zinc,  and  silver,  more  especially  in  mineral  veins  ;  but  is  also  found  in  cavities 
and  fissures  in  limestone  and  other  stratified  rocks.  It  usually  forms  groups 
of  distinct  crystals,  but  sometimes  presents  itself  in  columnar,  sub-fibrous, 
lamellar,  and  compact  examples.  The  crystals  as  a  rule  consist  of  simple 
cubes,  or  of  cubes  slightly  bevelled  on  the  edges  by  the  planes  of  a  tetrakis- 
hexahedron  (mostly  OC  3).  In  many  examples  the  cube-faces  present  a  four- 
fold series  of  striae,  meeting  in  a  point  at  or  near  the  centre  of  each  face. 
These  striae,  lines  of  growth  in  the  formation  of  the  crystal,  indicate  the  edges 
of  a  suppressed  tetrakis-hexahedron,  so  to  say.  Fluor  spar  is  often  colourless, 
but  more  frequently  it  presents  an  amethystine,  pale-green,  yellow,  or  deep 
blue-green  colour,  and  occasionally  a  rose-red  or  pearl-grey  tint.  The  cube 
edges  by  transmitted  light  often  show  a  shade  of  colour  more  or  less  .distinct 


180  BLOWPIPE    PRACTICE. 

from  that  of  the  faces  ;  and  columnar  or  fibrous  examples  are  frequently  zoned 
in  different  tints.  In  all  varieties  the  streak  is  white.  Hardness  between 
that  of  calcite  and  apatite,  or  equal  to  4  of  the  ordinary  scale.  Sp.  gr.  3 '15-3 '2. 
Most  examples  when  moderately  heated  exhibit  a  green  or  bluish  phosphor- 
escence ;  but,  if  a  fragment  be  heated  rapidly,  decrepitation  almost  invariably 
ensues.  By  fusion,  BB,  a  white  enamel  is  produced.  This  tinges  the  flame 
red,  and  reacts  alkaline  after  sufficient  ignition.  The  red  and  green  Ca-lines 
show  prominently  in  the  spectroscope,  if  a  small  splinter  be  held  for  a  few 
minutes  in  the  outer  edge  of  a  Bunsen-flame. 


[181] 


TABLE    XXI. 

[Lustre  non-metallic.  Readily  dissolved  BB  by  borax  or  phosphor-salt. 
Warmed  in  a  test-tube  with  sulphuric  acid,  evolve  orange-red  or  brownish 
nitrous  fumes.] 

A.— Anhydrous  Species.    Entirely  soluble  BB  in  carb.  soda. 

NITRE  (Saltpetre);  K20  46'53,  N2O5  53-47.  Rh.  (Y  :  Y  118°  49'); 
H2;  G  1*9-2-1;  normally  colourless.  Easily  soluble  in  water; 
taste,  saltish,  cooling.  BB  fusible  with  intumescence,  colouring  the 
flame-border  clear-violet.  On  charcoal,  deflagrates  and  is  absorbed. 

NITRATINE  (Chile  Saltpetre,  Soda  Nitre):  Na2O  36-47,  N2O5  63-53. 
Hemi-Hex.  (R  :  R  about  106°)  H  1-5-2  ;  G  2-l-2'2  ;  normally  colour- 
less, but  often  brownish  or  reddish  from  impurities.  Easily  soluble  ; 
taste,  saltish,  cooling.  Deliquescent.  Colours  flame  intensely  yellow; 
otherwise  like  potash-nitre. 

B  — Hydrated  Species.     In  carb.  soda,  BB,  only  partially 

soluble. 

NITROCALCITE  :  CaO  30-76,  N205  58-80,  IPO  10-44.  In  white  or 
greyish  earthy  efflorescences  on  the  walls  of  limestone  caverns,  cellars, 
&c.  Soluble  ;  deflagrating  by  ignition  on  charcoal,  leaving  a  white, 
earthy,  alkaline-reacting  crust. 

NITROMAGNESITE  :  Mg  0  24'10,  N2O»  65-10,  H2O  10-80.  Occurs 
with,  and  closely  resembles,  Nitrocalcite ;  but  the  white  crust,  left  BB 
on  charcoal,  exhibits  a  pink  tinge  after  ignition  with  cobalt-solution. 


NOTE  TO  TABLE  XXI. 

This  short  Table  comprises  the  three  or  four  representatives  of  the  group  of 
Nitrates  hitherto  recognized  as  minerals.  All  are  soluble  and  sapid.  By 
ignition  with  organic  bodies,  they  detonate  more  or  less  violently  ;  and  when 
warmed  with  sulphuric  acid,  or  fused  with  bisulphate  of  potash,  they  evolve 
reddish  or  brownish  nitrous  fumes.  The  bases  (magnesia  excepted)  are  readily 
recognized  by  the  spectroscope.  Soda  nitre  (often  erroneously  called  "  cubical 
nitre")  is  distinguished  also  from  ordinary  or  potash  nitre  hy  its  crystallization 
in  small  rhombohedrons,  its  deliquescence,  and  its  property  of  communicating 
a  deep  yellow  coloration  to  the  Bunsen  or  blowpipe  flame.  In  the  spectroscope, 
many  examples  shew  the  red  K-line  as  well  as  the  Na-line,  and  the  presence 
of  lime  ia  also  sometimes  revealed  (see  Part  I.,  page  55). 


[182] 


TABLE    XXII. 

[Lustre  non-metallic.  Easily  dissolved  BB  by  borax  or  phosphor-salt.  Forming 
by  fusion  with  carb.  soda  and  nitre  an  alkaline  salt  partly  soluble  in 
water,  the  solution  assuming  a  blue,  brown,  or  green  colour  by  boiling 
with  hydrochloric  acid  and  a  piece  of  tin  or  zinc. . 

A  —Anhydrous  Species.    Yielding  no  water  (or  merely  traces 
of  moisture)  by  ignition  in  bulb-tube. 

A»  -GIVING  LEAD  GLOBULES  OR  OTHER  FUSIBLE  METAL,  BB,  WITH  CARB.  SODA 

OR  ALONE. 

f  With  Borax,  BB.  a  bright-green  glass. 
(Streak,  strongly-coloured. ) 

CROCOISITE  (Crocoite):  PbO  69,  CrO8  31.  Clino-Rh.  (see  Note  at 
close  of  Table).  H  2-5-3;  G  5-9-6;  red;  streak  orange-yellow.  BB, 
generally  decrepitates  ;  fusible  and  reducible,  under  slight  detonation, 
on  charcoal.  Produces  chlorine  fumes  with  hydrochloric  acid. 
Forms  a  brown  or  yellow  solution  with  caustic  potash. 

PHOENICITE  :  PbO  77,  CrO3  23.  Rh.  (crystals  tabular,  indistinct), 
mostly  bladed  or  fibrous,  accompanying  Crocoisite.  Red;  streak, 
red;  H  3-3-5  ;  G  5-75.  Fusible  and  reducible. 

VAUQUELINITE  :  PbO  61-48,  CuO  10-95,  CrO  27-57.  Clino-Rh. 
(crystals  very  small,  indistinct),  commonly  in  coatings  and  botryoidal : 
H  2-5-3  ;  G  5-5-5-8.  Dark-green,  greenish-black  ;  streak  green.  BB, 
intumesces  slightly ;  fusible  and  reducible.  With  borax  in  R.  F. 
(especially  on  addition  of  tin)  forms  a  brick-red  opaque  bead  from 
presence  of  copper.  Laxmannite  is  a  variety  in  which  both  CrO3  and 
P2O5  are  present ;  but  this  is  probably  the  case  in  most  varieties  of 
Vauquelinite. 

DECHENITE  :  PbO  54-95,  Y?O5  45-05.  Mostly  in  small  botryoidal 
masses  or  groups  of  minute  indistinct  crystals;  H  3-5 ;  G  5-82  ; 
reddish-yellow,  brown;  streak,  yellow  or  orange.  Fusible  and 
reducible. 

EUSYNCHITE  :  essentially  a  lead  and  zinc  vanadate,  resembling 
Dechenite  in  colour  and  general  aspect. 

DESCLOIZITE  :  essentially  a  lead  vanadate  of  a  dark-green  or 
greenish-black  colour,  with  bands  of  yellow  or  brown. 

PUCHERITE  :  Bi2O3  71-74,  V2O5  28-26,  but  often  showing  traces  of 
P205  and  As20s.  Rh.  (crystals  very  small) ;  red,  brown ;  H  4 ; 


MINERAL  TABLES  : — XXII.  183 

G  6-25.  BB,  decrepitates,  and  yields  reduced  metal,  with  yellow 
ring  on  charcoal.  Soluble  in  hydrochloric  acid,  with  development  of 
chlorine  fumes,  the  red  or  yellow  solution  yielding  a  precipitate  on 
dilution. 

(Streak  white  or  indistinctly  coloured.) 

VANADINITE:  PbO  70-83,  V2O5  19-35.  PbCP  9-82.  Hex.  (iso- 
morphous  with  species  of  the  Apatite  group);  H  3;  G  6'8-7'2. 
Yellow,  reddish,  brownish.  BB,  decrepitates,  throws  off  sparks,  and 
gives  reduced  lead.  With  phos.  salt  and  CuO,  gives  azure  flame. 

f  f  With  Borax,  BB,  no  green  coloration;  but  green  or  blue  glass  with 
phosphor-salt  in  RF. 

WULFENITE:  PbO  61-4,  MoO3  38-6  Tet.;  H  3;  G  6-7 ;  yellow, 
yellowish-grey,  red  (the  latter  colour  due  apparently  to  presence  of 
lead  chromate),  rarely  colourless.  BB,  decrepitates,  melts  and  gives 
reduced  lead. 

STOLZITE:  PbO  49,  WO3  51.  Tet.  (see  Note  at  end  of  Table); 
H  3;  G  7-9-8-1  ;  grey,  also  green,  reddish,  and  brown.  BB,  melts 
easily  into  a  bead  which  crystallizes  on  cooling.  On  charcoal  in  RF, 
reduced. 

A«.— NO  REDUCED  LEAD  BB  ON  CHARCOAL. 

f  BB,  no  magnetic  globule. 

SCHEELITE:  CaO  19-45,  WO8  80-55.  Tet.  (see  Note  at  end  of 
Table);  H  4-5-5;  G  5 '9-6-2;  colourless,  greyish,  pale-yellow,  some- 
times red,  brown,  or  greenish ;  streak  white.  BB,  fusible  on  the 
edges,  or  in  thin  splinters  only. 

TUNGSTIC  OCHRE  :  W  79-3,  0  20-7.  In  earthy  coatings  of  a  yellow 
or  greenish  colour.  BC,  infusible,  blackens.  Insoluble  in  acids ; 
soluble  in  ammonia. 

MOLYBDIC  OCHRE  :  Mo  65-7,  O  34-3  In  earthy,  yellow  crusts  and 
coatings.  BB  easily  fusible.  On  charcoal,  absorbed  (if  pure).  Easily 
soluble  in  hydrochloric  acid. 

f  t  BB,  magnetic  globuU. 

WOLFRAM  :  MnO,  FeO,  WO3.  Dark-brown,  reddish-brown,  with 
dark  streak.  In  Clino-Rhombic  crystals  and  lamellar  masses,  which 
present  in  most  cases  a  sub -metallic  lustre.  H  5-5-5;  G  7-1-7-55. 
BB  fusible  to  a  magnetic  globule  with  crystalline  surface.  With 
carb.  soda,  strong  manganese-reaction.  See  Table  IX. 


184  BLOWPIPE    PRACTICE. 

B— Hydrous  Species.  Yielding  water  by  ignition  in  bulb-tube. 

(Cu  reaction.) 

YOLBORTHITE  :  CaO,  CuO,  V205,  H20  (5  per  cent.).  Hex.;  green, 
greenish-yellow;  streak,  yellow;  H  3;  G  3'5.  BB,  blackens,  and 
fuses  on  charcoal  into  a  dark  slag  containing  reduced  copper. 

(Cu  and  Pb  reactions.) 

MOTTRAMITE  :  CuO,  PbO,  Y2O5,  H2O  (37  per  cent.).  In  dark 
crystalline  coatings  with  yellow  streak  ;  H  3 ;  G  5*9.  On  sandstone 
from  Cheshire.  PSITTACINITE  (from  Montana)  is  a  related  compound 
in  green  sub-crystalline  and  botryoidal  coatings,  with  8  J  per  cent  H20. 


NOTE  TO  TABLE  XXII. 

This  Table  is  composed  essentially  of  Chromates,  Vanadates,  Tungstates, 
and  Molybdates.  The  two  first  may  generally  be  distinguished  from  other 
compounds  by  the  clear  emerald-green  glass  which  they  form  BB  with  borax 
in  a  reducing  flame.  The  colour  conies  out  in  its  full  purity  as  the  glass  cools. 
If  fused  in  a  platinum  spoon  with  carb.  soda  and  nitre  a  partially-soluble  salt 
results.  This,  in  the  case  of  Vanadates,  becomes  blue  when  warmed  with  a  few 
drops  of  hydrochloric  acid.  Chromates,  thus  treated,  give  a  green  solution. 
See  also  the  reactions  of  the  latter  described  in  PART  I.  of  this  work,  page  49. 
Tungstates  (in  the  absence  of  colouring  oxides)  form  BB  with  phosphor-salt  in 
the  RF  a  fine  blue  glass,  whilst  with  borax  the  glass  is  of  a  yellowish  or 
brownish  colour.  Molybdates  give  with  phosphor-salt  in  the  RF  a  fine  green 
glass.  See  also  the  distinctive  reactions  of  these  bodies  with  hydrochloric 
acid  and  zinc,  as  given  in  PART  I,  pages  46,  47,  62. 

With  the  exception  of  Wolfram  (a  species  which  commonly  presents  a  sub- 
metallic  aspect,  and  thus  belongs  more  especially  to  Table  IX. )  no  mineral  of 
this  Table  can  be  regarded  as  of  common  occurrence.  Attention,  however, 
may  be  directed  to  the  following :  the  chromate  Crocoisite,  the  molybdate 
Wulfenite,  and  the  tungstates  Wolfram,  Stolzite,  and  Scheelite. 

Crocoisite  is  readily  distinguished  by  its  fine  red  colour  and  orange-yellow 
streak,  and  by  the  emerald-green  glass  which  it  forms  BB  with  borax*.  It 
occurs  commonly  in  groups  of  small  or  acicular  crystals,  and  in  granular 
masses  and  coatings.  The  crystals  are  Clino-Rhombic  combinations  ;  most 
commonly,  vertically-striated  prisms  terminated  by  the  two  planes  of  an  acute 
heini-pyramid  ;  or  the  same  prism  terminated  by  a  very  acute  front-polar  or 
hemidome,  thus  closely  resembling  an  acute  rhombohedron. 

*  Deceptive  specimens  are  occasionally  made  by  placing  a  piece  of  quartz  in  a  crystallizing 
solution  of  bichromate  of  potash. 


MINERAL    TABLES  : XXII.  185 

Wulfenite  (molybdate  of  lead)  occurs  in  small  Tetragonal  crystals,  mostly 
of  a  yellow  or  yellowish-grey  colour,  but  orange-red  in  some  chromium  or 
vanadium- containing  varieties.  The  crystals  are  either  tabular  or  more  or  less 
flattened  parallel  with  the  base,  or  are  otherwise  small  pyramidal  combinations. 
As  pointed  out  by  Von  Kobell,  a  beautiful  azure-blue  coloration  originates  if 
the  finely-powdered  mineral  be  warmed  with  concentrated  sulphuric  acid  in  a 
porcelain  capsule,  and  some  alcohol  be  then  added. 

Stolzite  (tungstate  of  lead)  and  Scheelite  (tungstate  of  lime)  crystallize  also 
in  the  Tetragonal  System,  but  the  latter  often  occurs  in  crystals  of  half  an  inch 
or  more  in  length,  usually  a  simple  square-based  pyramid,  measuring  130°  33' 
over  the  base  or  middle  edge.  Stolzite  has  a  very  high  sp.  gr.,  7-'9-8'l,  and  is 
usually  grey  or  brownish  in  colour,  more  rarely  green  or  red.  Scheelite  has  a 
sp.  gr.  of  5  '9-6  2,  and  is  commonly  grey  or  greyish-yellow,  though  occasionally 
also  brown,  red,  or  green.  Both,  when  warmed  with  nitric  acid,  leave  a  yellow 
residuum  of  WO3,  soluble  in  caustic  alkalies. 

Wolfram  is  readily  distinguished  from  the  other  minerals  of  the  Table  by 
its  dark-brown  or  red-brown  colour  and  streak  ;  and  by  the  magnetic  globule 
which  it  yields,  before  the  blowpipe.  With  carb,  soda,  also,  it  gives  a  strong 
reaction  of  minganese.  Its  crystals,  as  a  rule,  are  of  comparatively  large  size. 
As  regards  their  general  character,  sw  Note  to  T^ble.  IX, 


[186] 


TABLE    XXIII. 

[Lustre  non-metallic.    Easily  dissolved  BB  by  borax  or  phosphor-salt,  but  not 
yielding  any  reaction  of  the  preceding  Tables.] 

A.— Streak  or  Powder  distinctly  coloured. 

A*.— MAGNETIC,  OR  BECOMING  SO  AFTER  STRONG  IGNITION. 

f  Anhydrous  species. 

MAGNETITE  (Magnetic  Iron  Ore) :  FeO  31,  Fe2O3  69.  Black,  with 
black  streak.  In  octahedrons  and  other  crystals  of  the  Regular 
System,  and  in  lamellar  and  granular  masses,  rarely  earthy.  H  5*5-6  -5  ; 
G  4-9-5-2.  Lustre,  commonly  sub-metallic.  See  Table  IX. 

MAGNOFERRITE  :  MgO,  Fe20s.  In  small  black  octahedrons,  as  a 
product  of  sublimation  of  Yesuvian  fumeroles.  Streak,  dark -brown  ; 
strongly  magnetic ;  G  4*65.  Accompanies  thin,  tabular  crystals  of 
Iron  Glance. 

JACOBSITE  :  MgO,  MnO,  Mn2Os,  Fe2O».  Reg. ;  granular  ;  black  ; 
streak,  reddish -black ;  H  5'5-6'0;  G  4-74-4-77  ;  strongly  magnetic; 
practically  infusible..  Strong  Mn  reaction  BB  with  carb.  soda.  In 
crystalline  limestone  from  Sweden. 

FRANKLINITE  :  ZnO,  MnO,  Fe203.  Reg.,  but  commonly  in  small 
rounded  masses.  Black  ;  streak,  brown  or  brownish-black.  More  or 
less  magnetic  in  most  examples.  H  6-6-5;  G  5-0-5-1.  Lustre 
mostly  sub-metallic  :  See  Table  IX.  BB,  in  powder,  with  carb.  soda 
and  borax  on  charcoal  gives  a  sublimate  of  ZnO.  With  carb.  soda, 
also,  strong  Mn  reaction. 

CHROMITE  :  FeO,  MgO,  APO3,  Fe20s,  Cr20s.  Reg.,  but  commonly 
in  granular  masses.  Brownish-black;  streak,  dark -brown.  Some- 
times magnetic.  Infusible.  With  borax,  BB,  fine  green  glass. 
Lustre,  commonly  sub-metallic.  See  Table  IX. 

ILMENITE  (Titaniferous  Iron  Ore):  Fe203,  Ti20s,  but  FeO  also 
present  in  some  varieties.  Hemi-Hex.;  iron-black,  mostly  with  sub- 
metallic  lustre.  H  5-6  ;  G  4-3-5-2,  commonly  about  4'9.  The 
hydrochloric  acid  solution,  diluted,  and  boiled  with  a  piece  of  tin  or 
zinc,  becomes  at  first  colourless  and  then  violet.  See  Table  IX. 

RED  IRON  ORE  (Haematite,  Red  Ochre,  &c.).  Fe203,  with  70  per 
cent.  Fe.  Hemi-Hexagonal;  but  when  of  non-metallic  aspect,  mostly 
in  fibrous-botryoidal,  lamellar,  or  earthy  examples.  Red,  brownish  or 


MINERAL  TABLES: — XXIIL  187 

bluish-red,  with  cherry-red  streak.  H  5-6,  or  lower  (1*5-3)  in  earthy 
and  sub-earthy  varieties;  G  4-8-5*3.  BB,  blackens  and  becomes 
magnetic.  Fusible  only  in  fine  splinters.  See  also  Table  IX. 

•f*  1*  Hydrous  species.      Yield  water  by  ignition  in  bulb-tube. 

BROWN  IRON  ORE  ( =  Gcethite,  Limonite,  Stilpnosiderite,  Lepi- 
dokrokite,  Yellow  Ochre,  &c.  These,  although  commonly  ranked  as 
distinct  species,  cannot  properly  be  regarded  otherwise  than  as 
varieties  of  Brown  Iron  Ore,  only  differing  from  one  another  by  their 
percentage  of  water,  a  character  by  no  means  absolutely  constant)  : 
Fe2O3  +  m  H2O,  with  Fe  60-63,  and  H2O  10-15  per  cent.  Eh. 
(Gcethite),  but  mostly  in  fibrous-botryoidal,  massive,  and  ochreous 
examples.  Dark-brown,  light-brown,  brownish-yellow,  with  yel- 
lowish-brown or  dull  yellow  streak ;  H  3-5-5-5  (but  lower  in  ochreous 
and  earthy  varieties) ;  G  3-2-4-2,  commonly  about  3.8-4-0.  BB,  yields 
water,  blackens,  and  becomes  magnetic.  Fusible  in  thinnest  splinters 
only.  TURGITE  is  a  closely  related  compound,  but  has  a  red  streak, 
and  yields  only  5-5 '5  per  cent,  water.  G  3*5-4 '5. 

OXALITE  (Humboldtine):  FeO  42*10,  Oxalic  Acid  42'10,  H20  15-80. 
In  hair-like  crystals,  fibrous  and  earthy  examples,  of  a  yellow  colour ; 
H  2 ;  G  2*1-2*25.  BB,  blackens,  becomes  magnetic,  and  then  becomes 
converted  into  red  iron-oxide.  If  a  particle  be  a  fused  into  a  bead 
of  borax,  coloured  blue  by  copper  oxide,  the  latter  becomes  rapidly 
reduced  to  Cu2O,  and  the  glass  becomes  opaque  red,  or  shews  red 
streaks,  on  cooling.  By  this  character,  Oxalite  is  readily  distinguished 
from  yellow-ochre. 

AS.— YIELDING,  BB,  WITH  CARB.  SODA  ON  CHARCOAL,  A  DISTINCT  SUBLIMATE 
AND  METALLIC  GLOBULES. 

MINIUM  (Mennige,  Red  Lead) :  Pb  90*7,  O  9-3.  Earthy;  or  pseudo- 
morphous  after  galena  or  cerussite ;  red ;  streak,  orange-yellow ;  H  2 
(or  less);  G  4*6-4*8.  BB,  darkens,  and  fuses  easily;  on  charcoal 
reduced.  In  HC1  acid  becomes  transformed  into  white  PbCl2,  with 
evolution  of  chlorine  fumes.  Partly  soluble  in  dilute  nitric  acid, 
leaving  residuum  of  puce-coloured  PbO2.  Insoluble  in  caustic  potash. 

MASSICOT  (Litharge;  Bleigliltte):  Normally,  Pb  92*8,  O  7*2,  but 
always  impure  from  presence  of  Fe2O8,  &c.  Fine  scaly,  earthy; 
sulphur-yellow,  orange-yellow ;  paler  in  the  streak;  G  7'8-8'0.  BB, 
easily  fusible  and  reducible.  Soluble  in  hot  solution  of  caustic 
potash,  and  reprecipitating  partly  in  crystalline  scales. 


188  BLOWPIPE    PRACTICE. 

BISMUTH  OCHRE  :  Bi  89-7,  O  10-3.  In  yellow,  grey,  or  greenish 
crusts  on  Native  Bismuth,  <fec. ;  G  about  4-5.  Fusible  into  a  yellow 
crystalline  bead  ;  on  charcoal  reducible. 

ZINCITE  (Spartalite) :  Gives  zinc  sublimate  with  carb.  soda,  but 
no  metallic  globules.  See  below. 

A«  -WITH  CARB.  SODA  ON  PLATINUM  WIRE,  DISTINCT  MANGANESE  REACTION. 

f  Anhydrous  Species. 

(BB,  zinc  sublimate  on  charcoal.     Streak,  orange-yellow. ) 
ZINCITE  (Spartalite):  Normally,  Zn  80'3,  O  19'7,  bnt  always  con- 
tains a  certain  percentage  of  Mn2O3.     Hex.,  but  commonly  in  lamellar 
or  granular  examples,  often  partly  coated  by  white  zinc-carbonate ; 
red;  streak  yellow;  H4;  G  5'5-5'7.     Infusible.     Soluble  in  acids. 

(BB,  no  sublimate  ;  no  copper  reaction.    Colour  and  streak,  black  or  dark-brown. ) 
BRA  UNITE  ;  HAUSMANNITE  :  In  small  crystals  (mostly  Tetragonal 

octahedrons)  or  granular  examples  of  dark-brown  or  iron-black  colour 

and  sub-metallic  lustre      G  4  -7-4  -9.     See  Table  X. 

PYROLUSITE  :    MnO2.      Iron-black,   very  soft,   mostly  in  fibrous 

masses  of  essentially  sub-metallic  lustre. ;  infusible.     See  Table  X. 

(BB,  with  borax  in  RF,  an  opaque-red  cupreous  bead.] 
CREDNERITE  :  CuO  43,  Mn'2O3  57.    In  iron-black,  cleavable  masses 
of  essentially  sub-metallic  lustre.      See  Table  X. 

1 1  Hydrous  Species. 

MANGANITE  :  Mn2O3,  H2O.  In  dark  steel-grey  or  iron-black 
crystals  and  other  examples  of  essentially  sub-metallic  (or  metallic) 
lustre.  H  3'5-4 ;  G  4-4.  See  Table  X. 

PSILOMELANE  :  MnO,  MnO2,  HO2,  in  somewhat  variable  propor- 
tions, with  part  of  MnO  replaced  by  BaO,  K20,  &c.  (See  Note  on 
page  119).  In  black,  granular  or  sub-fibrous  masses,  with  brownish- 
black  streak  and  more  or  less  dull,  earthy  aspect;  H  5-6  ;  G  4-0-4-4- 
Infusible,  or  fusible  on  the  edges  in  some  examples.  Occasionally  of 
sub-metallic  lustre.  See  Table  X. 

WAD  :  MnO,  Mn2O3,  H2O,  in  variable  proportions,  part  of  the  MnO 
always  replaced  by  BaO,  CaO,  or  K2O.  Properly,  a  mere  mixture 
or  decomposition  product.  In  brown  or  black,  earthy,  scaly,  stalac- 
titic,  or  botryoidal  examples,  occasionally  inclining  to  sub  metallic  in 
lustre,  H  1-0-3-0;  G  2-2-2-7.  Practically  infusible.  Grogroiliteis 
a  mixture  of  similar  character. 


MINERAL    TABLES  : XXIII.  189 

PYROCHROITE  (weathered  examples)  :  MnO,  H20,  mixed  with 
carb.  lime,  <fec.  Brown  or  black,  in  small  druses  in  magnetic  iron 
ore.  An  imperfectly  known  substance.  Normally,  white  and  pearly : 
see  under  §  B,  below. 

(BB,  with  borax,  strong  copper  reaction.) 
LAMPADITE  (Kupfermanganerz) :  CuO,  MnO,   BaO,  CaO,  Fe203, 

MnO2,   H20.     Properly,   a  mixture   or   product    of  decomposition. 

Amorphous;  black   or   brown;  H   2-0-3-5;    G  3-0-3-3.     Infusible; 

soluble  in  HC1  acid,  with  development  of  chlorine  fumes.     Kupfer- 

schwarze  and  Pelokonite  are  related  mixtures. 

ASBOLAN  :  CuO,  CoO,  K'O,  BaO,  Fe2O3,  MnO2,  H2O.     Resembles 

Lampadite  or  Wad  in  general  characters,  but  contains  cobalt  oxide. 

Rabdionite  is  a  similar  cobalt-holding  mixture. 

A*.— GIVING  COPPER  REACTION,  BUT  NO  MARKED  REACTION  OF  MANGANESE. 

CUPRITE  (Red  Copper  Ore,  Ruby  Copper):  Cu  88-8,  O  11-2  ( =  the 
suboxide  Cu2O).  Reg.,  commonly  in  small  octahedrons  or  rhombic 
dodecahedrons  often  coated  with  malachite,  also  massive,  &c.  Red, 
bluish-red,  with  lustre  frequently  inclining  to  sub-metallic ;  streak, 
red;  H  3-5-4  ;  G  5-7-6-0.  BB,  tinges  the  flame  green,  blackens, 
melts,  and  on  charcoal  is  reduced.  Soluble  in  hydrochloric  and  in 
nitric  acid,  also  in  ammonia.  See  Note  to  Table  IX.  Tile  Ore  is  a 
more  or  less  earthy  variety,  mixed  with  Fe2O3,  &c. 

HYDRO-CUPRITE  :  Cu2O  +  aq.  A  doubtful  species,  in  orange-yellow 
coatings  on  magnetic  iron  ore  from  Pennsylvania.  Recognized  by 
Genth. 

MELACONITE  (Black  Copper  Ore):  Cu  79-85,  O  20-15  (=CuO). 
In  black  earthy  coatings  on  certain  copper  ores,  also  massive  and  in 
pseudomorphous  cubo-octahedrons.  H  l'O-3'O;  G  6-2-6-3.  BB, 
fusible  and  reducible.  See  TENORITE  (the  same  compound,  but  with 
metallic  or  sub-metallic  lustre,  from  Vesuvius),  in  Table  IX. 

A*.— COLOURED  STREAK  OR  POWDER,  BUT  NO  REACTIONS  OF  FE,  PB,  MN,  OR  CU 
AS  IN  THE  PRECEDING  SECTIONS. 

(JBB,  with  borax,  strong  Co-reaction.) 

HETEROGENITE  :  CoO,  Co20s,  H2O  (21  per  cent.?)  mixed  with 
quartz,  brown  iron  ore,  &c.  Black  or  dark-brown ;  massive,  botry- 
oidal,  earthy.  A  product  of  decomposition  resembling  Asbolan  (see 
above)  but  giving  no  copper  reaction. 


100  BLOWPIPE    PRACTICE. 

(BB,  with  borax,  strong  Ni  reaction. ) 

BUNSENITE  :  Ni  78-6,  O  21-4.  Reg.  (minute  octahedrons);  H  5'5 ; 
G  6*4 ;  brownish-green,  yellowish-green.  Infusible.  With  carb.  soda 
on  charcoal  reducible  to  magnetic  grains. 

( Uranium  reaction.      Soluble  in  nitric  acid,  the  diluted  solution  giving  with 
ammonia  a  yellow  precipitate.) 

t  In  bulb-tube  no  water,  or  traces  only. 

PITCHBLENDE  :  UO,  U2O3,  more  or  less  impure  from  presence  of 
Fe,  Pb,  As,  &<:.  In  black  or  greenish-black  granular  masses  or 
disseminated  grains ;  H,  commonly,  about  5,  but  varying  from  4  to 
6  ;  G  5-0-8-0.  Infusible. 

t  f  In  bulb-tube  more  or  less  water. 

CORACITE  :  Impure  variety  of  Pitchblende  from  Lake  Superior. 
Black  ;  streak,  grey  or  greenish-grey;  H  4-5  ;  G  2-4-5-0.  Commonly 
mixed  with  CaO  CO2,  SiO2,  &c. 

GUMMITE  :  U2O3,  IPO,  mixed  with  CaO,  MgO,  Fe2O3,  P2O5,  SiO2, 
&c.  In  small  granular  masses,  strings  and  scattered  grains;  H  2-5-3*5 ; 
G  3'9-4'3  ;  yellow  or  yellowish-red  ;  streak,  yellow.  Infusible.  Eli- 
asite  (red-brown,  with  yellow  streak)  is  identical  or  closely  related. 

URAN  OCHRE  :  IPO3,  H20,  but  always  more  or  less  impure,  and 
commonly  mixed  with  uranium  sulphate.  In  earthy  or  fine-fibrous 
crusts  of  a  yellow  colour,  on  examples  of  Pitchblende. 

B.~ Streak-powder  uncoloured. 

BW REMAINING  WHITE  ON  IGNITION  IN  BULB-TUBE. 

t  Anhydrous  Species. 

PERICLASE  :  Mg  60,  O  40.  Reg.  (in  minute  octahedrons,  cubo- 
octns.,  or  cubes);  cleavage,  cubical ;  H  6*0  ;  G  3-65-3-75  ;  dark-green  ; 
vitreous ;  infusible.  Hitherto  only  found  at  Monte  Somma  in  ejected 
limestone  masses. 

1 1  Hydrous  Species. 

BRUCITE  :  MgO  69,  H2O  31,  but  often  partially  converted  into 
carbonate.  Hemi-Hex.  (R  :  R  82°  22',  but  crystals  mostly  tabular 
from  predominance  of  basal  plane).  Commonly,  however,  in  scaly, 
foliated,  and  sub-fibrous  masses.  H  2;  G  2 -3-2 -4;  white,  greenish- 
white  ;  lustre  pearly  on  B  plane.  Infusible.  Nemalite  is  an  asbesti- 
form,  fibrous  variety,  white  or  pale-bluish  in  colour. 


MINERAL    TABLES  : XXIII.  191 

VOLKNERITE  (Hydrotalcite) :  MgO,  APO3,  FevO«,  CO2,  H2O.  A 
mixture  of  Brucite  with  alumina-hydrate,  <fec.,  or  a  product  of  decom- 
position. White  '}  foliated,  or  in  tabular  hexagonal  crystals  '}  H  2  ; 
G  15 '0-2 '1.  BB,  exfoliates,  but  remains  unfused. 

B«.— BLACKENING  ON  IGNITION  IN  BULB-TUBE. 

(After  strong  ignition,  assume  a  pink  colour  by  treatment  BB  with  cobalt 

solution). 

BRUCITE  :  MgO,  H3O.  Occasional  examples :  see  above.  Alkaline 
reaction  after  ignition. 

( With  carb.  soda,  BB,  strong  manganese-reaction). 

PYROCHROITE  :  MnO  79-8,  H2O  2O2.  In  white,  foliated  masses, 
forming  strings  in  certain  examples  of"  magnetic  iron  ore,  but 
weathering  brownish-black  from  conversion  of  the  MnO  into  higher 
degree  of  oxidation.  BB,  blackens ;  infusible. 

(Ca-lines  in  spectroscope,  and  alkaline  reaction,  after  ignition). 
WHEWELLITE:  CaO  38-36,  C2O3  49-31,  H20  12-33.     Clino-Rh. ; 
in  small  (commonly  twinned)  crystals  on  certain  examples  of  Calcite. 
Colourless;  lustre vitreo-adamantine ;  H2-5-2-0;  G  1'83;  infusible; 
by  gentle  ignition  converted  into  CaO,  CO*. 


NOTE  ON  TABLE  XXIII. 

This  Table  is  composed  essentially  of  Oxides.  The  more  commonly  occurring 
spjecies,  belonging  to  it,  may  be  grouped  in  four  series,  as  follows  : — (1),  Iron 
Ores  and  related  compounds ;  (2),  Manganese  Oxides ;  (3),  Red  Zinc  and 
Copper  Oxides  ;  and  (4),  the  magnesia  hydrate,  Brucite. 

The  Iron  Ore  group  comprises,  chiefly,  (i)  the  anhydrous  species  of  Regular 
crystallization,  Magnetite,  Franklinite,  and  Chromite  (with  common  formula 
KO,  Pt203) ;  (ii)  the  anhydrous  Hemi-Hexagonal  species,  Haematite  and  Ilmenite 
(with  common  formula  R203) ;  and  (iii)  the  hydrous  species,  conveniently  ranked 
together  under  the  common  name  of  Brown  Iron  Ore  (with  common  formula  = 
R^O3  +  m  H'O).  All  the  species  of  this  group  become  magnetic  after  ignition 
or  semi-fusion,  and  several  are  magnetic  in  their  normal  condition.  In  most 
cases  the  finely  powdered  ore  dissolves  without  much  difficulty  in  hot  hydro- 
chloric acid,  but  Chromite,  Ilmenite,  and  titaniferous-holding  Magnetite  are 
exceptions.  The  two  latter  in  the  form  of  very  fine  powder  generally  yield  to 
slow  digestion  (in  a  small,  covered  beaker  on  a  sand  bath,  the  acid  being  kept 
just  at  the  boiling  point),  but  Chromite  (unless  mixed  with  magnetite)  is  very 
slightly  attacked.  It  may  be  decomposed  however  (sufficiently  for  determina- 
tive purposes)  by  gentle  fusion,  in  tine  powder,  with  a  mixture  of  carb.  soda, 


192  BLOWPIPE    PRACTICE. 

borax,  and  nitre.  By  this  treatment  an  alkaline  chromate,  soluble  in  water, 
is  formed.  The  solution,  decanted  from  the  insoluble  residuum,  may  then  be 
evaporated  to  dryness,  and  the  resulting  deposit  fused  with  borax  for  the  pro' 
duction  of  a  chrome-green  glass.  The  presence  of  chromium  may  also  be 
shewn  by  the  deep  green  coloration  produced  by  addition  of  sulphuric  acid 
and  alcohol :  see  PART  I.,  page  49. 

Comparatively  few  examples  of  Magnetite  are  referrible  to  the  present 
Table,  as  in  most  specimens  of  that  mineral  the  lustre  is  unmistakably  metallic 
or  sub-metallic  (see  TABLES  VIII.  and  X.).  Some  examples,  however,  are 
obscurely  metallic  in  aspect.  These  are  black  in  colour,  with  black  streak, " 
and  strongly  magnetic.  Commonly  in  granular  or  lamellar  masses,  with  G 
averaging  5'0.  When  crystallized,  in  octahedrons  and  rhombic  dodecahedrons. 

Franklinite  and  Chromite  much  resemble  examples  of  Magnetite  with 
obscurely  metallic  lustre.  They  are  mostly  in  black,  granular  masses,  with 
normally  dark  brown  or  red  brown  streak,  but  the  latter  is  often  black  from 
presence  of  magnetite,  or  greenish  from  intermixed  chloritic  or  pyroxenic  rock- 
matter.  Franklinite  is  often  strongly  magnetic  (probably  from  presence  of 
Fe304).  Chromite  is  only  occasionally  magnetic,  and  its  specific  gravity  falls 
below  4 '6,  averaging  .usually  4 '3  or  4 '4.  Franklinite  with  carb.  soda,  BB, 
forms  a  turquoise  enamel  (Mn  reaction),  and  gives  oh  charcoal  (if  treated  in 
powder  with  carb.  soda  and  borax)  a  sublimate  of  ZnO.  Chromite  with  borax 
gives  (on  cooling)  a  fine  green  glass.  See  also  its  reactions  described  above. 

Ilmenite  resembles  the  above  minerals  by  its  black  colour  and  brownish  or 
black  streak,  as  well  as  by  its  frequent  occurrence  in  granular  or  scaly  granular 
masses ;  but  its  crystals  are  rhombohedral  combinations  closely  resembling 
those  of  Haematite  (R :  R  85031').  It  is  most  readily  distinguished  by  the 
deep  amethystine  colour  which  results  when  its  hydrochloric  acid  solution 
(somewhat  diluted)  is  boiled  for  a  few  minutes  with  a  piece  of  tin. 

Haematite  occurs  under  several  more  or  less  distinct  conditions  ;  but  in  most 
cases  it  presents  a  metallic  or  well-marked  sub-metallic  aspect,  and  is  thus 
referred  to  in  preceding  Tables  (see  Notes  to  TABLES  VIII.  and  X.).  The 
examples  belonging  more  especially  to  the  present  Table  commonly  come 
under  the  designation  of  Red  Iron  Ore,  of  which  Reddle .  or  Red  Ochre  is  an 
earthy  variety.  In  these,  the  streak  is  always  distinctly  red,  and  the  colour 
either  brick-red,  brownish-red,  or  bluish-red,  the  lustre  in  the  latter  case 
merging  into  sub-metallic.  The  harder  examples  are  very  frequently  in  fibro- 
botryoidal  masses.  BB,  in  the  RF,  all  blacken  and  become  magnetic. 

Brown  Iron  Ore  includes  several  so-called  species  or  sub-species,  compounds 
of  Fe203  with  variable  amounts  of  water.  All  yield  a  yellow  or  yellowish- 
brown  streak  ;  and  all  become  red  by  ignition  with  free  access  of  air  (especially 
in  powder),  the  water  being  driven  off.  Ordinary  varieties  assume  a  bright 
red  colour  on  ignition,  but  varieties  which  contain  much  manganese  give  a 
dull-red  or  chocolate-red  powder.  Before  the  blowpipe  in  a  reducing  flame, 
all  become  black  and  magnetic,  and  fine  splinters  exhibit  fusion.  Practically, 
these  compounds  may  be  referred  to  three  series  : — (i)  a  series,  typified  by 
Goethite,  in  which  the  water  averages  10  per  cent.,  the  formula  being  Fe30*, 


MINERAL    TABLES  : — XXIII.  193 

H26  ;  (»)  a  second  series,  typified  by  Limonite,  the  formula  of  which  may  be 
written  Fe'O3,  3  H20,  with  14  to.  15  per  cent,  water;  and  (Hi),  a  series  of 
Bog  ores  and  Ochres  containing  20  per  cent,  or  more  water,  and  having  part 
of  the  iron  in  the  condition  of  FeO  combined  with  Immic  or  other  organic 
acid.  No  very  strict  lines  of  demarcation  can  be  drawn,  however,  between 
these  varieties.  Gcethite,  although  frequently  in  fibrous  and  other  examples, 
occurs  occasionally  in  thin-scaly  and  acicular  crystals  of  the  Rhombic  System. 
The  other  Brown  Ores  are  unknown  in  true  crystals,  although  cubes  and  other 
pseudomorphs  derived  from  Iron  Pyrites  are  not  uncommon.  They  occur 
chiefly  in  fibro-botryoidal,  granular,  and  earthy  masses.  Many  of  the  fibrous 
examples  present  a  silky  lustre,  and  some  are  comparatively  light  in  colour. 
Many  brown  ores,  also,  shew  a  variegated  surface-tarnish. 

The  group  of  Manganese  Oxides — referrible  as  regards  some  examples  to 
the  present  Table — includes  the  comparatively  rare  species  Braunite  and 
Hausmannite,  characterized  chiefly  by  occurring  in  small  Tetragonal  crystals 
of  a  brownish-black  colour  and  more  or  less  sub-metallic  aspect  (see  TABLE 
X.);  certain  examples  of  Pyrolusite  and  Manganite,  occurring  mostly  in  dark 
fibrous  masses  or  crystal  groups,  usually  of  metallic  or  well-marked  sub- 
metallic  lustre  (see  TABLES  VIII.  and  X.);  and  the  amorphous  Psilomelane, 
with  the  earthy,  ochreous  mixtures  known  as  Wad.  The  two  latter  alone 
belong  properly  to  this  Table  ;  and  Psilomelane  in  many  of  its  examples 
presents  a  more  or  less  metallic  aspect  (see  TABLE  VIII. ).  These  manganese 
oxides,  if  warmed  in  powder  with  hydrochloric  acid,  cause  the  evolution  of 
chlorine  fumes,  a  character  by  which  they  are  readily  distinguished  from  bodies 
of  similar  aspect.  The  green-blue  enamel  which  they  form,  BB,  with  carb. 
soda,  is  also  highly  distinctive.  Ignited  by  a  Bunsen-flame  and  examined  by 
the  spectroscope,  nearly  all  examples  shew  green  Ba-lines,  and  Psilomelane 
and  many  Wads  shew  in  addition  the  red  K-line,  and  occasionally  the  crimson 
Li-line.  (See  Foot  Note,  page  119). 

Pyrolusite  and  Wad  are  of  low  hardness,  and  thus  soil  more  or  less  dis- 
tinctly. Wad  yields  water  on  ignition  ;  Pyrolusite  is  anhydrous.  The  other 
manganese  oxides  of  natural  occurrence  range  in  hardness  from  about  4'0 
(Manganite)  to  5 '5  or  6'0.  Psilomelane  and  Manganite  yield  water  on 
ignition  :  Braunite  and  Hausmannite  are  anhydrous ;  but,  as  already  remarked^ 
these  latter  species  scarcely  require  notice  in  the  present  Table,  as  their  lustre 
in  ordinary  examples  is  at  least  sub-metallic. 

The  group  of  red  zinc  and  copper  oxides  includes  merely  Zincite  and  Cuprite. 
Zincite  or  Red  Zinc  Ore,  ZnO  (with  part  replaced  by  MnO),  is  chiefly  dis- 
tinguished by  its  red  colour,  orange  streak,  and  infusibility.  With  carb.  soda 
and  borax,  BB,  on  charcoal,  it  gives  a  characteristic  zinc  sublimate,  and  also 
a  strong  reaction  of  manganese.  It  occurs  chiefly  in  cleavable  and  scaly- 
granular  masses,  usually  associated  with  Frankliuite.  The  crystallization  is 
Hexagonal,  with  basal  cleavage,  but  crystals  are  rarely  met  with. 

Cuprite  (Red  Copper  Ore  or  Ruby  Copper)  occurs  commonly  in  octahedrons 
(often  with  sunk  faces)  and  in  rhombic  dodecahedrons  and  other  forms  and 
combinations  of  the  Regular  System,  frequently  converted  into  green  carbonate 
14 


194  BLOWPIPE    PRACTICE. 

on  the  surface.  It  is  also  found  in  acicular  groups  and  in  lamellar  and  other 
masses  ;  and  in  a  dull,  sub-earthy  condition  (mixed  with  Fe'203,  &c. )  forming 
the  so-called  "Tile  Ore."  Its  more  distinctive  characters  are  its  red  colour 
and  streak,  and  its  easy  reduction,  BB  on  charcoal,  to  metallic  copper.  It 
dissolves  with  effervescence  and  production  of  coloured  nitrous  fumes  in  nitric- 
acid,  forming  (as  in  the  case  of  copper  compounds  generally)  a  green  solution 
which  becomes  intensely  blue  on  addition  of  ammonia. 

Brucite,  MgO,  H20,  is  easily  distinguished  from  the  other  commonly 
occurring  minerals  of  this  Table  by  its  white  streak,  softness,  pearly  aspect, 
and  its  magnesia-reaction,  BB,  with  nitrate  of  cobalt.  On  ignition  it  evolves 
30  to  31  per  cent,  water,  and  reacts  alkaline. 


\ 


[195] 


TABLE    XXIV. 

[Lustre  non-metallic.  BB,  slowly  attacked  or  only  in  part  dissolved  by  borax 
or  phosphor-salt.  Infusible,  or  fusible  on  thinnest  edges  only.  Hardness 
sufficient  to  scratch  ordinary  window-glass  distinctly.  *] 

A.— Insoluble  (in  powder)  in  hydrochloric  acid. 

Ai.—  SPECIFIC  GRAVITY  OVER  5'0. 

f  With  carb.  soda  and  a  little  borax,  BB,  yielding  metallic  tin. 
CASSITERITE  (Tinstone): — Sn  78-62,  0  21-38,  but  most  examples 
contain  traces  of  Fe203,  Mn203,  &c.  Tetragonal  (crystals  often 
twinned),  see  Note  at  end  of  Table;  also  massive  and  in  rolled 
pebbles  (  =  stream-tin,  wood-tin)  often  with  sub-fibrous  structure. 
Brown,  black,  grey,  reddish,  &c.,  rarely  colourless;  H  6-0-7-0;  G 
6-7-7-0.  Infusible,  but  reducible  on  charcoal  (especially  if  fused 
with  carb.  soda,  cyanide  of  potassium,  or  neutral  oxalate  of  potash). 

1 1  With  carb.  soda,  BB,  forming  a  slaggy  mass  or  remaining 
undissolved.     Streak  more  or  less  distinctly  coloured. 

[This  subsection  includes  only  some  comparatively  rare  species  (essentially 
Tantalates,  Niobates,  Nio-titanates)  in  which  the  lustre  on  the  fractured  sur- 
face is  distinctly  sub-metallic,  at  least  in  typical  examples.  These  species 
belong  properly,  therefore,  to  Table  X.  When  they  occur  in  a  fragmentary 
form,  or  are  indistinctly  crystallized,  their  correct  determination  is  not  easily 
effected.  In  most  examples,  traces  of  tin  are  obtained  by  the  reduction  process 
with  carb.  soda  and  borax  ;  and  by  fusion  in  fine  powder  with  bisulphate  of 
potash,  all  are  more  or  less  decomposed,  the  fused  mass  becoming  blue  when 
warmed  with  a  few  drops  of  hydrochloric  acid  and  a  piece  of  tin  or  zinc.] 

(BB,  unchanged). 

TANTALITE:  FeO,  Ta2O5,  <fec.;  Rhombic;  black;  H  6-0-6-5;  G 
6-3-8-0,  usually  7-0-7-5. 

*  Minerals  in  which  the  normal  degree  of  hardness  scarcely  exceeds  5-0  do  not  scratch  glass 
very  distinctly ;  and  if  slightly  weathered  or  altered  they  may  not  scratch  glass  at  all.  To 
avoid  risk  of  error,  therefore,  infusible  silicates  of  this  character  are  placed  both  in  the  present 
Table  and  in  Table  XXV.  In  trying  the  hardness  of  a  mineral  by  a  piece  of  glass,  the*  glass 
should  be  laid  flat  on  a  table,  and  the  mineral  drawn  with  rather  strong  pressure  sharply  across 
it — care,  of  course,  being  taken  that  no  particles  of  quartz  are  attached  to  the  substance. 
Several  species  placed  in  this  Table  are  not  absolutely  infusible  when  tested  in  the  form  of  a 
very  fine  splinter,  although  melting  even  then  at  the  extreme  point  only,  and  requiring  practice 
on  the  part  of  the  operator  to  effect  this  ;  but,  to  avoid  uncertainty  in  cases  of  this  kind,  the 
species  in  question  are  referred  to,  again,  in  either  Table  XXVI.  or  Table  XXVII.— the  first 
Containing  fusible  anhydrous  silicates,  and  the  latter,  hydrated  species. 


196  BLOWPIPE   PRACTICE. 

COLUMBITE  (Dianite):  FeO,  MnO,  Nb2O5,  Ta'Os,  &c.;  Rhombic; 
black,  generally  somewhat  iridescent;  H  6-0;  G  5-37-6-5.  In  fine 
powder  partially  attacked  by  hot  sulphuric  acid. 

MBNGITE:  YO,  CeO,  ZrO2,  TiO*,  &c.;  Eh.;  black;  H  5-5 ;  G 
5-4.8.  Decomposed  by  hot  sulphuric  acid. 

(BB,  becoming  yellow  or  pale- greyish  and  yielding  a  little  water  in  the  bulb-tube) 
YTTHOTANTALITE:  YO,ErO,FeO,Ta2Os,  WO8,  &c.;  black,  brownish, 

yellow,  often  spotted;  H  5*0-5-5;  G  5-4-5-8. 

FERGUSONITE  ;  POLYCRASE  ;  EUXENITE  ;  ^ESCHYNITE  : — See  TABLE 

X.,  pages  126,  127. 

(BB,  partially  fused  or  attacked  on  the  surface  or  edges). 
SAMARSKITB  :  YO,  FeO,  CeO,  U2O3,  Nb2O5,  Ta2O*,  &c.;  Rhombic; 
black;  streak  red-brown;  H  5-0-6-0;    G  5*6-5 '8.     Decomposed  in 
powder  by  hot  sulphuric  acid. 

A2. -SPECIFIC  GRAVITY  3 -3-5-0. 

f  With  carb.  soda,  ££,  forming  a  slag  only,  or  remaining  undissolved, 

(H  =  10.     In  fine  powder  slowly  combustible). 

DIAMOND  (Crystallized  Carbon): — Reg.,  crystal-faces  often  curved 
(see  Note  at  end  of  Table).  Colourless,  pale  yellowish  or  variously 
tinted,  sometimes  black;  lustre  strongly  adamantine;  H  10;  G 
3-5-3-55,  but  in  the  black  "  carbonado  "  variety  sometimes  slightly 
lower.  BB,  in  fragments,  unaltered  per  se  and  not  attacked  by  the 
fluxes,  but  in  fine  powder  slowly  combustible. 

(BB,  with  Co-solution,  APO*  reaction). 

CORUNDUM  (Sapphire,  Ruby,  Adamantine  Spar,  Emery):  Al  53-2f 
O  46-8  (  -  A12O3).  Hexagonal  (see  Note  at  end  of  Table).  H  9-0  ; 
G  3-8-4-2,  usually  3-9-4-0.  Pink,  blue,  red,  brownish,  colourless, 
dark-grey — the  latter  in  the  opaque  variety  Emery ;  many  crystals 
colourless  at  one  extremity,  and  blue  or  reddish  at  the  other.  BB, 
quite  infusible ;  the  powder  fused  with  bisulphate  of  potash  forms  a 
salt  soluble  in  water.  Ammonia  throws  down  gelatinous  APO* 
(generally  somewhat  brownish  from  accompanying  Fe20s)  from  the 
solution. 

DIASPORE:  APO3  85,  H20  15.  Rhombic,  but  often  in  foliated 
or  scaly  masses;  H  6-6 -5 ;  G  3-3-3-5.  Colourless,  white,  brown7 
violet,  greenish,  &c.  In  bulb-tube  generally  decrepitates,  gives  off 
Crater,  and  falls  into  scaly  particles.  BB,  like  Corundum. 


MINERAL   TABLES  : — XXIV.  197 

TOPAZ  :  APO3,  SiO2,  Fl.  Rhombic  (see  Note  at  end  of  Table) ; 
H  8-0;  G  3-5-3-57;  yellow  of  various  shades,  pale  bluish^green, 
reddish-white,  colourless ;  cleavage  very  perfect,  parallel  with  basal 
plane.  Infusible,  but  becomes  colourless  and  loses  polish  on  strong 
ignition.  BB,  with  fused  phosphor-salt  in  open  tube,  gives  fluorine 
reaction.  Pycnite  and  Physalite  are  columnar,  opaque  or  semi- 
opaque  reddish-white  or  straw-yellow  varieties. 

CHRYSOBERYL  (Cymophane):  BeO  19-8,  APO3  80-2;  Rhombic 
(see  Note  at  end  of  Table);  H  8-0-8-5;  G  3-65-3-85;  green  of  various 
shades,  greenish- white  (often  shewing  a  floating  opalescence),  and  in 
anany  examples  pale-red  by  transmitted  light.  BB,  like  Corundum. 

SPINEL  :  Normally,  MgO  28,  APO3  72,  but  part  of  the  MgO  com- 
monly replaced  by  FeO,  and  part  of  the  APO3  by  Fe2O3.  Reg, 
{crystals  mostly  small  octahedrons,  often  twinned :  see  Note  at  end 
of  Table).  H  8-0;  G  3-5-4-1,  usually  about  3-55-3-6.  Red,  blue, 
green,  of  various  shades;  reddish-white,  black,  rarely  colourless. 
BB  infusible,  but  .many  red  varieties  appear  green  whilst  hot. 
Decomposed  in  powder  by  fusion  with  bLsulphate  of  potash. 

SAPPHIRINE:  Essentially  composed  of  MgO,  FeO,  APO3,  SiO'. 
Occurs  in  small  granular  masses  in  mica-slate  from  Greenland  ;  light- 
blue,  bluish  or  greenish-grey;  H  7'5  ;  G  3-42-3-47.  Infusible. 

CYANITE  (Disthene) :  APO8  62-10,  SiO2  36-90.  Anorthic,  but 
•chiefly  in  bladed  or  flat-fibrous  masses ;  H  7'0  on  edges  of  crystals  or 
laminae,  5-5-5  on  flat  surfaces ;  G  3-48-3-68.  Bluish- white,  light-blue, 
grey,  pale-green,  reddish-white,  tile-red.  Infusible. 

(Zn  reaction  by  fusion  in  powder  with  mixture  of  carb.  soda  and  borax 

on  charcoal)* 

GAHNITE  (Automolite)  :  ZnO  38*7,  APO3  61-3,  but  small  amounts 
of  MgO,  MnO,  FeO  and  Fe2O3  also  frequently  present.  Reg.  (crystals 
mostly  small  octahedrons,  commonly  twinned  as  in  Spinel) ;  H  7 -5-8  0 ; 
G  4-0-4-6 ;  dark  green,  greenish-black.  Dysluite  is  a  manganese- 
holding  variety ;  Kreittonite  a  ferruginous  variety.  BB,  infusible  ; 
the  powder  fused  with  equal  parts  of  earb.  soda  and  borax  gives  a 
.zinc  sublimate. 

(Fe  reaction*). 

PLEONASTE  (Ceylanite) :  Black  or  dark-green  variety  of  SPINEL, 
.see  above,  containing  as  a  rule  too  much  iron  to  give  a  distinct 

•*  A  small  particle,  or  some  of -the  powder,  added  to  a  bead  of  borax  coloured  by  copper- 
.-oxide,  Quickly  reduces  part  of  the  CuO  to  red  CusO. 


198  BLOWPIPE    PRACTICE. 

A1203  reaction  with  Go-solution.  HERCINITE  (mostly  in  small  dull- 
black  granular  masses)  is  still  more  ferruginous,  practically  all  the 
MgO  being  replaced  by  FeO.  In  these  dark  varieties  the  sp.  gr.  is 
usually  about  3*9  or  4-0. 

STAUROLITE  (Staurotide) :  Composed  essentially  of  FeO,  MgO, 
APO3,  SiO2.  Khombic  :  (crystals  often  cruciform  twins,  essentially 
rhombic  prisms,  with  V:Y  near  129°,  truncated  on  acute  edges); 
H  7-0-7-5;  G  3-4-3-8;  brownish-red,  dark-brown.  BB  (as  regards- 
true  Staurolite)  infusible.  In  powder  attacked  by  sulphuric  acid. 
See  Note  at  end  of  Table. 

(Chrome  reaction :  BB,  with  borax,  emerald-green  glass). 
UWAROWITE  (Ouvarovite,   Chrome  Garnet):  CaO,   APO3,   Cr2O3, 
SiO2.     Reg.    (crystals,  small   rhombic-dodecahedrons) ;   H    7-5 ;    G 
3-4-3*53;  bright  green.     Infusible. 

(Sp.  &r.  4-0-4-7). 

ZIRCON  (Hyacinth):  ZrO2  67,  SiO2  33.  Tetrag.  (crystals,  com- 
monly, eight-sided  prisms  with  pyramidal  termination) ;  H  7*5 ;  Gr 
usually  about  4*4;  yellowish-brown,  grey,  light-brown,  red,  rarely 
.  greenish  or  colourless.  Infusible.  Slowly  attacked  by  sulphuric 
acid.  See  Note  at  .end  of  Table.  Auerbachite,  Ostranite,  and 
Malakon  (Tachyaphalite),  are  probably  slightly  altered  varieties,  the 
latter  yielding  3  per  cent,  water.  H  about  6-5 ;  G  3'9-4'l. 

( Yielding  water  in  bulb-tube). 

OERSTEDITE:  MgO,  ZrO2,  TiO2,  SiO2,  HSO  (5-6  percent.).  Tetrag. ; 
H  5-5-6-0;  G  3-63;  red-brown,  brownish-yellow,  with  adamantine 
lustre.  A  rare,  imperfectly-known  species,  allied  to  and  resembling 
Zircon. 

MALAKON  :  An  altered  Zircon :  see  above. 

f  f  With  carb.  soda,  BB,  dissolving  more  or  less  readily  or  forming  en 

fused  glass. 
(Titanium  reaction). 

KUTILE  :  TiO2.  Tetragonal  (crystals  essentially  prismatic,  often 
geniculated  twins,  sometimes  acicular) ;  H  6-0-6-5  ;  G  4*2-4-3 ;  red 
(with  strong  adamantine,  often  sub-metallic,  lustre),  black  (Nigrine, 
mostly  in  rolled  pebbles),  yellowish-brown ;  streak,  pale-brown 
BB,  unchanged.  Fused  in  fine  powder  with  carb.  soda  (or  better 
with  caustic  soda  or  potash)  forms  a  salt  soluble  in  hydrochloric 


MINERAL    TABLES  : — XXIV.  199 

acid,  the  solution,  slightly  diluted  and  boiled  with  a  piece  of  tin  or 
zinc,  assuming  a  violet  colour. 

ANATASE  or  OCTAHEDRITE  :  TiO2.  Tetrag.  (crystals,  small  square- 
based  octahedrons  or  pyramids) ;  H5'5-6'0;  G  3 -8-4-0  ;  indigo-blue, 
brownish,  yellowish-grey,  with  adamantine  often  sub-metallic,  lustre. 
BB,  like  Rutile. 

BROOKITE  :  TiO2.  Rhombic  ?  (V  :  V  99°  50' ;  V  :  V  139°  55' ; 
P:P  in  front  115°  43',  at  side  101°  35',  crystals  mostly  tabular); 
H  5-5-6-0 ;  G  4-0-4-25 ;  light-brown,  yellowish,  reddish,  black  in 
Arkansite  variety ;  lustre  adamantine  to  sub-metallic.  BB,  like 
Rutile. 

A3. -SPECIFIC  GRAVITY  UNDER  3 '3. 

f  With  carb.  soda,  B&,  forming  a  slag  or  semi-fused  mass. 

TOURMALINE  (Light-coloured,  red,  green,  and  other  infusiblo 
varieties) :  Essentially  composed  of  MgO,  A12O3,  B2O3,  SiO2,  with 
small  amounts  of  Na20,  Li2O,  Fl,  <fec.  Hemi-Hexag.  (crystals  mostly 
nine-sided  prisms,  longitudinally  striated,  with  differently  modified 
summits  :  R :  R  about  133°  10',  - 1  R  152°  -  2  R  103°  3') ;  green, 
brown,  red  (Rubellite),  blue  (Indicolite),  colourless;*  H  7 -0-7 '5  : 
G  2-9-3-2  ;  pyro-electric.  Infusible,  or  slightly  attacked  BB  on  thin 
edges,  as  regards  the  varieties  belonging  to  this  Table.  The  powder 
ignited  in  a  platinum  spoon  and  boiled  with  a  few  drops  of  sulphuric 
acid,  communicates  a  green  tinge  to  the  flame  of  alcohol  or  to  the 
point  of  the  blowpipe-flame.  In  many  varieties,  also,  the  ignited 
powder  moistened  with  hydrochloric  acid  shews  the  red  Li-line  in 
the  spectroscope. 

ANDALUSITE  (Chiastolite) :  A1203  63,  SiO2  37.  Rhombic  (V  :  V 
90°  50'  -  91°  4') ;  H,  normally,  7-0-7 '5,  but  often  lower  from  partial 
alteration;  G  3-10-3 -20 ;  greyish-white,  pearl-grey;  pale  violet,  red, 
reddish- white,  greenish.  BB,  infusible ;  with  Co-solution,  after 
ignition,  assumes  a  tine  blue  colour.  CHIASTOLITE  is  a  variety  in 
narrow  straw-like  crystals,  or  occasionally  in  thick  prisms,  imbedded 
in  clay  slate,  mica  slate,  &c.,  and  presenting  on  the  transverse  section 
a  dark  cross  or  black  lozenge-shaped  figure  arising  from  a  symmetrical 
arrangement  of  the  rock-substance  in  the  centre  and  at  the  angles  of 
the  hollow  prismatic  crystal. 

*  The  black  opaque  varieties  known  as  Schorl,  and  many  brown  varieties  are  easily  fusible, 
See  TABLE  XXVI. 


200  BLOWPIPE    PRACTICE. 

SILLIMANITE:  APO3  36-9,  SiO2  63-1.  Rhombic  in  crystn.,  but 
commonly  in  fibrous  or  bladed  examples ;  H,  normally,  6-7 ;  G 
3 '2-3-3;  pale  brown,  yellowish-grey,  greenish.  BB,  like  Andalusite 
and  Cyanite,  these  three  minerals  being  identical  in  composition  and 
closely  related  in  other  respects.  Fibrolite,  Bucholzite,  Xenolite, 
Monrolite,  and  Wcerthite,  are  varieties. 

IOLITE  (Dichroite,  Cordierite) :  MgO,  FeO,  APO3,  SiO2,  with 
usually  traces  of  MnO,  and  frequently  (from  alteration)  a  small 
amount  of  H2O.  Rhombic  (mostly  in  short  stout  crystals  of  pseudo- 
hexagonal  aspect,  with  Y:Y  119°  10'),  but  commonly  in  granular 
examples;  H,  normally,  7 '0-7 '5 ;  G  2  -5-2  -7 ;  blue,  smoky-grey; 
brownish  or  yellowish  in  certain  directions  by  transmitted  light. 
BB,  fusible  with  difficulty  on  thin  edges ;  with  Co-solution  becomes 
bluish-grey  or  pale-blue. 

ft  With  carb.  soda  BB  forming  a  fused  glass  or  bead.* 
(Cleavage-planes  more  or  less  distinct). 

EUCLASE:  Essential  composition:  BeO,  APO3,  SiO2  (41-43  per 
cent.),  with  a  small  percentage  of  water  only  driven  off  by  intense 
and  prolonged  heat,  and  therefore  not  detected  in  ordinary  blowpipe 
operations.  Clino-Rhombic  :  (crystals  much  resembling  the  common 
augite  crystals,!  small  and  brilliant) ;  H  7'5 ;  G  3'0-3'1  ;  colourless, 
pale-green,  bluish-white.  BB,  in  fine  splinters,  becomes  opaque, 
blisters  slightly,  and  becomes  rounded  at  the  extreme  'point.  With 
carb.  soda  in  proper  proportion,  forms  an  opaque  pearl.  A  very  rare 
species. 

BERYL  (Emerald) :  BeO  14-14,  APO3 19-05,  SiO2  66-84,  with  traces 
of  Fe2O3,  and  in  the  bright-green  varieties  (Emerald)  a  small  amount 
of  Cr2O3.  Hexagonal  (crystals  mostly  six-sided  prisms  with  large 
basal  plane);  H  7-5-8-0;  G  2-66-2-76;  pale  green,  greenish-white, 
emerald-green,  occasionally  pale  yellow,  bluish,  or  quite  colourless. 
BB,  in  fine  splinters,  becomes  opaque  white,  and  melts  with  difficulty 
at  the  extreme  point. 

PHENAKITE:  BeO  45-78,  SiO'  54-22.  Hex.  or  Hemi-Hex. ;  H 
7-5-8-0;  G  2-9-3-0;  colourless,  pale  yellowish.  BB,  infusible.  With 

*  The  flux  should  be  added  little  by  little.  With  too  much,  or  too  small  a  quantity,  imperfect 
results  are  obtained. 

fBy  atomic  constitution,  and  also  by  crystallization,  Euclase  is  regarded  as  related  to 
Datolite;  but  the  actual  composition  and  geological  relations  of  these  minerals  are  very 
different. 


MINERAL    TABLES  : — XXIV.  *  201 

small  amount  of  carb.  soda  melts  to  a  white  bead ;  with  larger 
quantity  forms  a  slag.  A  very  rare  species. 

ENSTATITE  :  MgO  40,  SiO2  60,  but  with  part  of  the  MgO  replaced 
by  small  amount  of  FeO.  Rhombic  (V:V  91°  44'  -  93°) ;  mostly 
in  greenish- white,  grey,  or  green  cleavable  masses;  H  5'5  to  nearly 
6-0;  G  3-10-3-29.  BB,  fusible  on  thinnest  edges  only.  Bronzite, 
commonly  regarded  as  identical,  is  here  kept  distinct  on  account  of 
its  inferior  hardness.  See  TABLE  XX Y. 

ORTHOCLASE  (Potash  Feldspar) :  K2O  16-9,  APO3  18-4,  SiO2  64-7. 
Clino-Rh.  (crystals  often  twinned:  see  Note  to  .TABLE  XXVI.); 
commonly  in  cleavable  masses  (the  adjacent  cleavage-planes  meeting 
at  90°)  of  a  white,  red,  greyish,  or  light-green  colour;  H  6*0;  G 
2-5-2-6.  BB,  fusible  with  difficulty  or  on  the  edges  only,  but  a  fine 
splinter  is  readily  vitrified  at  the  point.  Red  K-line  clearly  visible 
in  spectroscope  if  the  powder  be  ignited  and  then  moistened  with 
hydrochloric  acid,  or  fused  with  carb.  soda. 

ALBITE  (Soda  Feldspar):  Essentially,  Na2O  11-8,  AK)3  19-6, 
SiO2  68  6.  Anorthic  (crystals  often  twinned  :  see  Note  to  TABLE 
XXVI.) ;  commonly  in  white,  red,  or  other-coloured  cleavable  masses, 
with  adjacent  cleavage-planes  meeting  at  93°  36'  and  86°  24',  one 
of  these  planes  being  generally  striated.  H  6-0  ;  G  2  58-2-64.  BB, 
(in  fine  splinters)  difficultly  fusible,  tinging  the  flame-border  strongly 
yellow.* 

TRITOMITE  :  Normally,  pure  SiO2,  but  differing  from  quartz  (although 
belonging  to  the  same  System  of  Crystallization)  by  the  character  of 
its  crystals,  the  indications  of  cleavage  which  it  shews  in  one  direction, 
its  somewhat  lower  sp.  gr.,  and  its  solubility  in  a  saturated,  boiling 
solution  of  carb.  soda.  H  7*0 ;  G  2-28-2-33 ;  colourless,  opaque 
white.  The  crystals  are  mostly  tabular  from  predominance  of  the 
basal  plane  (practically  unknown  in  quartz),  or  in  fan-shaped  or 
other  twins. 

ASMANNITE  :  Normally  SiO2,  but  differing  essentially  from  quartz 
and  tritomite  by  its  Rhombic  crystallization,  closely  identical  with 
that  of  Brookite.  H  5-5  ;  G  2-245-2-247.  Recognized  by  Maskelyne 

*  These  feldspars  are  referred  to  in  the  present  Table,  because  they  are  commonly  regarded 
as  infusible  by  students  who  have  had  but  little  practice  with  the  blowpipe,  or  who  persist  in 
testing  fragments  of  too  large  a  bulk.  They  are  described  again  in  their  proper  place,  with 
Anoitbite  and  other  distinctly  fusible  feldspars,  in  TABLE  XXVI. 


202  BLOWPIPE    PRACTICE. 

(in  small  cleavable  grains  with  indications  of  rhombic  crystallization) 
in  the  meteoric  iron  of  Breitenbach  in  Bohemia. 

(No  observable  cleavage  planes). 

QUARTZ  (Rock  crystal,  Amethyst,  Calcedony,  Agate,  <fcc.) :  Normally, 
pure  silica;  Si  46 -67,  O  53-33,  but  often  coloured  by  traces  of  Fe203, 
Mn2O,  &c.  Hexagonal  or  Hemi-Hexagonal  (see  Note  at  end  of 
Table) ;  crystals,  commonly  six-sided  prisms  striated  transversely 
and  terminated  by  a  six-sided  pyramid ;  often  massive,  botryoidal, 
granular;  H  7'0  ;  G  2-5-2-8  (clear  examples  and  crystals  commonly 
about  2-65);  colourless,  white,  violet,  smoky-brown,  pink,  red,  green, 
grey,  black,  &c.,  the  colours  of  massive  examples  often  in  stripes  or 
spots  :  see  Note  at  close  of  Table.  BB  unchanged.  With  carb.  soda 
fusible  with  effervescence  (due  to  expulsion  of  CO2)  into  a  clear  glass. 

OPAL  (Hyalite,  &c.):  SiO2,  with  from  2  to  20  per  cent.  H2O  :  the 
latter  usually  3-10  per  cent.  Opaque  and  strongly  coloured  varieties 
also  contain  intermixed  Fe203and  other  impurities.  Uncrystalline,  and 
thus  normally  without  action  on  polarized  light.  In  nodular,  botry- 
oidal, and  other  massive  examples ;  H  (normally)  5-5-6-5  ;  G  1-5-2-5, 
commonly  1-9-2-2;  colourless,  bluish-white,  yellowish-red,  with  in- 
ternal play  of  colours  or  iridescence  (Noble  Opal,  Girasol,  Fire-Opal) ; 
also  colourless,  forming  vitreous  coatings  or  botryoidal  masses  011 
lava  (Hyalite) ;  or  white,  yellow,  brown,  red,  bluish-grey,  &c.,  often 
in  stripes  or  patches  in  the  same  specimen,  and  with  more  or  less 
waxy  or  sub-resinous  lustre  (Common  Opal,  Semi-Opal,  Wood  Opal, 
&c.).  BB  usually  decrepitates ;  in  the  bulb-tube  yields  a  little  water; 
otherwise  like  quartz.  In  powder,  soluble  in  hot  solution  of  caustic 
potash.  Jasper  Opal  is  an  opaque  red,  dull-yellow  or  brown  variety, 
mixed  with  a  considerable  amount  of  Fe2O3  or  Fe203,  H2O.  Menilite 
is  a  light-brown  or  bluish-grey  variety  in  flat  nodular  pieces.  Pearl- 
sinter,  Siliceous  Sinter,  Geyserite,  &c.,  are  stalactitic,  encrusting  or 
porous  varieties,  deposited  by  many  hot  springs.  Tripoli,  Polishing 
Earth,  Raiidanite,  are  forms  of  amorphous  silica,  made  up  of  minute 
tests  or  coverings  of  diatoms. 


MINERAL    TABLES  :— XXIV.  203 

B.—  Readily  decomposed  or   dissolved  (in  powder)  by  hot 
hydrochloric  acid.* 

Bi.- YIELDING  NO  WATER  (OR  TRACES  ONLY)  BY  IGNITION  IN  BULB-TUBE. 

f  Decomposed,  without  gelatinization,  by  hydrochloric  acid. 

LEUCITE:  K20  21-53,  APO  23-50,  SiO2  54-97,  but  part  of  the 
K2O  commonly  replaced  by  Na2O.  Tetrag.,  but  crystals  closely 
resembling  a  trapezohedron  of  the  Regular  System.  H  5'5-6'0;  G 
2-45-2-50 ;  white,  light-grey,  yellowish  or  reddish- white.  Only  found 
in  crystals  or  small  rounded  masses  in  certain  lavas.  Infusible ;  with 
Co-solution,  BB,  assumes  a  bright  blue  colour.  In  fine  powder, 
•decomposed  by  hydrochloric  acid,  with  separation  of  granular  silica. 
Shews  red  K-line  distinctly  in  spectroscope  when  ignited  and  fused 
with  carb.  soda  or  moistened  with  hydrochloric  acid. 

POLLUX  :  Cs'O,  Na2O,  A12O3,  SiO2,  with  about  2J  per  cent.  H2O, 
the  latter  easily  escaping  detection  in  the  examination  of  small 
fragments.  Reg.  (crystals  very  minute  combinations  of  cube  and 
trapezohedron  2-2).  Commonly  in  small  camphor-like  colourless, 
masses.  H  5-5-6-5;  G  2-8-2-9.  Fusible  only  on  thin  edges.  The 
powder  heated  with  fluoride  of  ammonium  and  then  moistened  with 
hydrochloric  acid  shews  in  the  spectroscope  the  two  characteristic 
Ccesium  lines.  These  are  bright  blue  and  close  together,  one  being 
almost  in  the  position  of  the  blue  Sr-line.  A  rare  species,  hitherto 
only  found  in  the  Island  of  Elba. 

f  f  Decomposed,  with  separation  of  gelatinous  silica,  by 
hydrochloric  acid. 

(Zn  reaction :  characteristic  ring-deposit  on  charcoal  by  fusion  of  test-substance 

with  carb.  soda). 

WILLEMITE  :  ZnO  73,  SiO2  27.  Hemi-Hex.  (crystals  commonly 
six-sided  prisms  terminated  by  an  obtuse  rhombohedron  of  128°  30', 
but  very  small,  and  often  with  rounded  edges);  H  5*5;  G  3-9-4-2  ; 
white,  brownish,  red,  green,  <kc.  Infusible,  or  attacked,  BB,  on 
thinnest  edges  only. 

(Zn  and  Mn  reactions). 
TROOSTITE  :  Like  Willemite  in  composition  but  with  part  of  the 


*  Reduce  a  small  fragment  (5  or  6  grains,  or  less)  of  the  test-substance  to  powder ;  place  this 
(by  means  of  a  folded  slip  of  glazed  paper)  at  the  bottom  of  a  clean  test-tube ;  twist  a  rolled  - 
up  piece  of  soft  paper  round  the  top  of  the  tube  to  serve  as  a  handle,  the  ends  of  the  paper 
being  twisted  together;  cover  the  powder  to  the  depth  of  about  half-an-inch  with  strong 
hydrochloric  acid,  and  boil  gently  (letting  the  flame  touch  the  side  of  the  tube  near  the  top  of 
the  acid)  for  two  or  three  minutes. 


204  BLOWPIPE  PRACTICE. 

JZiiO  replaced  by  MnO  and  FeO.  Hemi-Hex.  (crystals  comparatively 
large,  mostly  six-sided  prisms  with  rhombohedral  terminations). 
Commonly  opaque  or  semi-opaque,  yellowish-grey,  greenish  or  brown. 
BB  with  carb.  soda  forms  a  turquoise- enamel.  Otherwise  like 
Willemite.  Properly,  a  manganese  variety  of  the  latter  species. 

(Fl  reaction  with  sulphuric  acid). 

CHONDRODITE  :  MgO,  FeO,  SiO2  (33-37  per  cent.),  MgFP.  Clino- 
Rh.,  but  commonly  in  small  granular  masses  of  a  yellow,  yellowish- 
white,  reddish,  brown,  or  green  colour  imbedded  in  cryst.  limestone  : 
H  6-0-6-5 ;  G-  3-0-3-25.  BB  infusible,  or  rounded  only  on  thinnest 
edges.  CLINO-HUMITE  is  closely  related.  • 

HUMITE  :  a  Chondrodite  of  Rhombic  crystallization.  In  small 
crystals  with  numerous  pyramidal  planes,  and  generally  a  well- 
developed  basal  plane,  chiefly  from  Monte  Somma,  but  recognized 
also  by  E.  Dana  (with  Chondrodite  and  Clino-Humite)  from  Brewster, 

N.Y. 

(No  Zn  or  Fl  reaction.     G  3'0  to  3 -5). 

CHRYSOLITE  or  OLIVINE  (Peridot):  Average  composition,  MgO  49, 
FeO  10,  SiO2  41 ;  but  in  some  varieties  the  FeO  is  higher,  and  MnO 
and  TiO2  are  occasionally  present.  Rhombic,  but  often  in  small 
granular  masses  in  basalt,  &c.  H  6 -5-7-0 ;  G  3-2-3-5.  Green  of 
various  shades,  yellow,  brownish,  rarely  yellowish-red.  BB,  infusible, 
except  as  regards  some  very  ferruginous  varieties  (Hyalosiderite,  &c.) 
which  yield  a  magnetic  slag  or  globule :  see  TABLE  XXVI.  Forsterite 
(Boltonite)  is  identical  in  composition,  crystallization  and  other  charac- 
ters. Hortonolite  and  Glingite  are  ferruginous  varieties. 

MONTICELLITE  (Batrachite)  :  Average  composition,  CaO  35,  MgO 
22,  FeO  5-5,  SiO2  37-5.  Rh. ;  H  5-5;  G  3-12;  colourless,  greyish, 
pale  greenish  or  yellowish-grey.  BB,  rounded  on  thinnest  edges 
only.  Ignited  and  then  moistened  with  HC1  acid,  shews  in  spectro- 
scope momentary  red  and  green  Ca-lines. 

GEHLENITE  :  Essential  composition,  CaO,  A1203,  SiO2  with  small 
amounts  of  MgO,  FeO,  Fe'O3,  and  H2O;  Tetrag.  (crystals  chiefly 
simple  square  prisms) ;  H  5-5-6-0;  G  2-98-3-10;  pale  greenish-grey, 
green,  brownish.  BB,  rounded  on  thin  edges.  In  spectroscope  (after 
ignition  and  moistening  with  HC1)  shews  Ca-lines  very  distinctly. 

(G  4  or  higher ;  colour,  black). 

GADOLINITE  :  YO,  CeO,  BeO,  FeO,  SiO2,  with  traces  of  H2O,  and 
occasionally  small  amounts  of  ErO,  CaO,  &c.  Rhombic  or  Clino-Rh., 


MINERAL   TABLES  : — XXIV. 

hut  chiefly  in  small  granular  masses  without  distinct  cleava^^-i'p^ac^  V^  v 
greenish-black;  streak  greenish-grey ;.  H   6-5-7 '0;   G   4-0-4-3,     BB, 
many  varieties  emit  a  peculiar  glow,  and  most  examples  swell  up 
slightly  and  become  greenish-grey,  but  none  exhibit  fusion,  properly 
so-called. 

B2.— YIELDING  WATER  ON  IGNITION.* 

( BB,  strong  Cu-reaction  with  borax,  or  when  moistened  with  hydrochloric  acid)  „ 
DIOPTASE  :  CuO  50-44,  SiO2  38-12,  H2O  11-44.  Hemi-Hexagonal 
(crystals  chiefly  combinations  of  hexag.  prism  and  rhombohedron, 
with  angle  of  95°  2Sr  over  polar  edges  of  the  latter) ;  cleavage  rhom- 
bohedral,  with  R :  R  1 25°  54r;  bright  emerald-green,  with  paler  streak ; 
H  5fO-5-5;  G  3-27-3-35.  BB,  generally  decrepitates,  blackens,  but 
remains  unftised.  With  carb.  soda,  on  charcoal,  gives  metallic  copper. 
Gelatinizes  in  hydrochloric  acid.  A  rare  species.  The  amorphous 
capper  silicate,  Chrysocolla,  has  normally  a  low  degree  of  hardness, 
and  is  decomposed  by  hydrochloric  acid  without  gelatinization.  See 
TABLE  XXY. 

(BB,  with  carb.  soda  on  charcoal,  zinc  reaction). 

CALAMINE  :  ZnO  67-5,  SiO2  25,  H2O  7-5.  Rhombic  (crystals  hemi- 
morphic,  i.e.,  with  different  terminations,  but  generally  small,  and 
somewhat  indistinct);  H  5*0;  G  3-3-3'5;  colourless,  or  variously 
tinted.  The  crystals  pyro-electric.  Frequently  in  botryoidal  and 
other  massive  examples.  BB,  infusible ;  commonly  decrepitates. 
Decomposed  with  gelatinization  by  hydrochloric  acid. 

(No  reactions  of  Cu  or  Zn.     G  4 '9  to  5'0). 

CERITE  :  CeO,  SiO2,  H2O  (6-12  per  cent.),  but  with  part  of  the 
CeO  constantly  replaced  by  LaO,  DiO,  CaO,  &c.  Hexag.  (?);  mostly 
in  massive  examples  of  a  red,  reddish-grey,  or  brownish  colour ;  H 
5-5  ;  G  4-9-5-0.  Gelatinizes  in  hydrochloric  acid.  The  solution  (if 
not  too  acid)  gives  with  oxalic  acid  a  white  precipitate  which  becomes 
converted  into  tile-red  Ce20*  by  ignition  in  the  platinum  spoon  (Yon 
Kobell). 

(G  under  3'0), 

POLLUX  :  Yields  on  ignition  a  very  small  amount  of  water.  Mostly 
in  small  colourless  camphor-like  masses.  See  under  B1,  above. 

*  The  minerals  of  this  section  belong  properlj  to  Table  XXV.,  as  they  scratch  glass- more  or 
less  indistinctly,  but  to  avoid  risk  of  error  in  their  determination  they  are  referred  to  also 
here. 


206  BLOWPIPE    PRACTICE. 

NOTE  ON  TABLE  XXIV. 

This  Table  includes  a  series  of  hard,  infusible  or  very  difficultly  fusible 
minerals  of  vitreous  or  other  non-metallic  lustre ;  with,  in  addition,  a  few 
species  in  which  the  lustre  is  occasionally  sub-metallic.  These  latter  are 
comparatively  rare,  and  they  belong  normally  to  Table  X. 

The  following  are  the  only  species  of  importance,  or  of  ordinary  occurrence, 
which  possess  sufficient  hardness  to  scratch  glass  distinctly :— (1)  The  Dia- 
mond; (2)  a  group  of  closely  allied  Tetragonal  species,  comprising:  Cassiterite, 
Rutile,  Anatase,  Zircon  ;  (3)  the  purely  or  essentially  aluminous  species, 
Corundum,  Chrysoberyl,  Spinel,  Gahnite ;  (4)  the  purely  siliceous  species, 
Quartz  and  Opal ;  and,  (5),  the  silicates,  Topaz,  Beryl,  Cyanite,  Andalusite, 
Staurolite,  Chrysolite,  Chondrodite,  Tourmaline,  lolite,  Leucite,  Orthoclase, 
Albite.  » 

The  Diamond  is  distinguished  essentially  by  its  extreme  hardness,  its  peculiar 
adamantine  lustre,  and,  in  ordinary  examples,  by  its  crystallization.  The 
latter  is  Regular,  but  the  crystals  have  almost  invariably  curved  planes. 
The  principal  forms  comprise  the  tetrahedron  and  octahedron,  and  the 
adamantoid  3'1'f,  the  last  often  distorted  both  by  curvature  of  faces  and  by 
elongation.  The  cleavage  is  octahedral.  In  the  Bunsen  flame  on  platinum 
foil,  diamond  dust  burns  slowly  away,  but  small  splinters  remain  unchanged. 

The  Tetragonal  species,  Cassiterite,  Rutile  and  Anatase,  have  the  common 
formula  RO2 ;  and  with  these,  from  its  close  correspondence  in  crystallization 
with  Rutile,  the  Zircon  may  be  placed.  Cassiterite,  SnO2,  is  readily  distin- 
guished by  its  high  sp.  gr.  (67-7'0),  and  by  yielding  reduced  tin,  BB,  with 
carb.  soda  or  other  reducing  flux  on  charcoal.  The  crystals  are  commonly 
short  eight-sided  prisms,  terminated  by  the  planes  of  the  two  corresponding 
square  pyramids  (without  basal  plane);  and  they  are_very  frequently  in 
geniculated  twins.  P :  P  over  polar  edge  =  121°  40' ;  P :  P  =  133°  30'.  In 
mineral  veins,  Cassiterite  is  very  generally  associated  with  Wolfram  and 
Quartz,  the  latter  forming  the  gangue  or  veinstone.  The  variety  known  as 
"stream  tin"  occurs  in  small  rolled  pebbles  and  grains  in  alluvial  deposits. 
"Wood  tin"  is  also  an  uncrystallized  variety  of  light  or  dark  brown  colour 
and  concentric-radiated  structure.  Rutile,  TiO2,  distinguished  in  ordinary 
examples  by  its  red  or  brown  colour  and  adamantine  lustre,  closely  resembles 
Cassiterite  in  crystallization,  and  especially  in  its  geniculated  twin-forms  ; 
p :  P  =  123°  8' ;  vertical  planes,  in  general,  longitudinally  striated.  Rutile 
occurs  also  occasionally  in  acicular  radiating  crystals,  traversing  quartz  ;  and 
in  small  dark  pebbles  (Nigrine).  Anatase  or  Octahedrite,  another  form  of 
TiO2,  is  mostly  in  small  pyramidal  crystals  of  a  greyish-brown  or  peculiar  blue 
colour,  with  adamantine,  more  or  less  sub-metallic  lustre.  The  crystals  com- 
monly shew  a  consecutive  series  of  several  pyramids,  but  are  sometimes  tabular 
from  extension  of  the  basal  plane.  The  angle  over  middle  edge  in  Pr=136°  36' 
(over  polar  edge  97°  51') ;  in  |  P,  79°  54' ;  in  i  P,  53°  22' ;  in  f  P,  39°  30'. 
Both  Anatase  and  Rutile,  and  the  Rhombic  species  Brookite,  after  fusion  in 
fine  powder  with  carb.  soda,  are  dissolved  by  hydrochloric  acid.  The  solution 
assumes  a  deep  violet  colour  if  slightly  diluted  and  boiled  with  metallic  tin. 


MINERAL  TABLES  : — XXIV.  207 

Zircon,  ZrO2,  SiO2,  occurs  occasionally  in  small  granular  masses,  but  most 
commonly  in  simple  crystals  of  the  Tetragonal  System.  These  are  frequently 
small  square  prisms  terminated  by  a  square  pyramid  measuring  123°  20'  over 
polar  edges,  and  84°  20'  over  middle  edges.  The  basal  plane  is  always  absent. 
Other  common  crystals  are  eight-sided,  from  combination  of  the  two  square 
prisms,  and  in  many  a  second  pyramid  is  subordinately  present.  Some  crystals, 
again,  shew  the  planes  of  one  or  more  octagonal  pyramids,  3  P  3,  4  P  4,  5  P  5, 
but  these  planes  are  usually  quite  narrow  or  of  small  size.  Zircon  is  mostly 
red  or  red-brown  in  colour,  but  sometimes  pale  yellowish-grey,  orange-yellow, 
greenish,  or  colourless.  Its  hardness  (7  "5),  and  its  high  sp.  gr.  which  averages 
4 '4  or  4-5,  and  always  exceeds  4'0,  are  salient  characters.  BB  loses  colour, 
but  is  quite  infusible.  The  powder  is  slowly  taken  up  by  borax,  the  saturated 
glass  becoming  opaque  when  flamed. 

Corundum,  A1203,  is  distinguished  by  its  great  hardness  (9'0),  its  high  sp. 
gr.  (3 '8-4*2),  hexagonal  or  hemi-hexagonal  crystallization,  and  complete  infusi- 
bility  ;  and  by  the  fine  blue  colour  imparted  to  it  by  treatment,  BB,  with 
cobalt  solution.  It  occurs  under  three  more  or  less  distinct  conditions  :  (1) 
in  small  transparent  or  sub-transparent  crystals  of  a  blue,  pink,  red,  or  other 
colour,  or  sometimes  colourless,  forming  the  sapphire,  ruby,  &c. ,  of  jewellers, 
according  to  the  colour;  (2)  in  coarser  translucent  or  opaque  crystals  and 
cleavable  masses  of  a  greyish-green,  red,  brown  or  other  tint,  forming  the 
variety  known  as  Adamantine  Spar  ;  and  (3)  in  fine-granular  masses  of  a  grey 
or  dark  bluish-grey  or  black  colour,  commercially  known  as  Emery.  The  latter 
variety  is  sometimes  mixed  with  grains  of  magnetic  iron  ore.  The  Corundum 
crystals  are  mostly  small,  pyramidal  combinations,  or  six-sided  prisms  with 
narrow  pyramidal  planes  and  large  basal  face,  and  are  frequently  ill-formed. 
The  cleavage  is  basal,  and  also  rhombohedral,  with  R :  R  86°  4'.  Many  crvstals 
are  parti -coloured,  blue  and  white,  &c. ;  and  in  some  (asteria  sapphire),  a  six- 
rayed  opalesceuce  is  visible.  The  cleavage  faces  often  shew  a  delicate  striation. 
For  blowpipe  reactions,  see  the  Table. 

Chrysoberyl,  BeO,  A1203  (or  perhaps  Be'O8,  APO3),  is  a  comparatively  rare 
species  of  a  green  or  greenish -white  colour,  sometimes  reddish  by  transmitted 
light,  and  often  shewing  a  pale-bluish  opalescence — whence  the  name  Cymo- 
phane,  by  which  this  species  is  also  known.  The  crystals  are  Rhombic  com- 
binations, and  are  frequently  in  pseudo-hexagonal  stellate  groups* — both  simple 
and  compound  crystals  being  generally  more  or  less  tabular  from  extension  of 
the  front  vertical  form  or  macro-pinakoid  V.  The  hardness  of  chrysoberyl 
(8 '5)  nearly  equals  that  of  corundum  ;  and  its  comparatively  high  sp.  gr. 
(3 7-3'8)  is  also  distinctive. 

*  Compound  stellate  and  hexagonal  groupings  are  common  among  crystals  of  the  Rhombic- 
System  (Chrysoberyl,  Marcasite,  Discrasite,  Aragonite,  Cerusite,  &c.),  and  are  occasionally 
seen  in  CHno-Rhombic  and  Regular  crystals  (the  latter  in  Camphor,  &c.),  but  are  apparently 
unknown  among  minerals  and  chemical  products  of  recognized  Hexagonal  crystallization.  Th<- 
beautiful  snow-crystalg  so  common  in  Canadian  -winters  are  thus  most  probably  not  tiulv 
hexagonal,  but  compound  Rhombic  forms.  See  a  brief  communication  by  the  writer  in  the 
Canadian  Journal,  1860. 


-OS  BLOWPIPE    PRACTICE. 

Spinel,  normally  MgO,  APO3,  is  readily  distinguished,  in  most  examples,  by 
its  occurrence  in  small  octahedrons,  commonly  twinned,  as  well  as  by  its  great 
hardness  (8'0),-  and  its  high  specific  gravity  (3'5-4'l).  The  colour  is  usually 
some  shade  of  red,  but  colourless  and  other-coloured  varieties  are  also  known. 
After  fusion  in  fine  powder  with  bisulphate  of  potash  it  is  partially  soluble  in 
water.  Ammonia  throws  down  flocculent  A1203  from  the  solution. 

Gahnite  is  properly  a  zinciferous  spinel,  commonly  in  small  octahedrons, 
both  simple  and  twinned,  of  black  or  dark-green  colour,  with  greenish-grey 
streak.  Combinations  of  the  cube  with  the  rhombic  dodecahedron  and  several 
trapezohedrons,  are  also  known.  The  simple  octahedral  crystals  resemble 
generally  those  of  magnetic  iron  ore,  but  from  this  species  Gahnite  is  distin- 
guished by  its  want  of  magnetism,  its  pale  streak,  lower  sp.  gr.  and  greater 
hardness,  as  well  as  by  the  zinc  sublimate  which  it  yields  when  fused,  in 
powder,  with  a  mixture  of  about  equal  parts  of  carb.  soda  and  borax,  on 
charcoal. 

Quartz,  SiO2,  is  distinguished  readily  from  the  preceding  minerals  by  its 
much  lower  sp.  gr.,  as  this  never  exceeds  2 '7  or  2 '8.  Also  by  fusing  readily 
with  carb.  soda,  and  forming  with  that  reagent  a  clear  glass.  Its  want  of 
distinct  cleavage  is  also  characteristic.  When  crystallized,  it  is  almost  in- 
variably in  six-sided  pi'isms,  streaked  across  and  terminated  by  the  planes  of 
a  regular  hexagonal  pyramid,  the  basal  plane  being  always  absent.  The 
pyramid-planes  ?are  often  very  irregular  in  size  and  shape.  The  principal 
angles  are  as  follows  :  over  polar  edge,  133°  44';  over  point  of  crystal,  76°  26'; 
on  adjacent  prism-plane,  141°  47'.  If  the  pyramid  be  regarded  as  consisting  of 
two  complementary  rhombohedrons,  R  on  R  equals  94°  1 5';  and  in  many 
crystals  only  three  terminal  planes  of  this  kind  are  present  ;  or  the  six  planes 
differ  alternately  in  size,  so  as  to  form  two  sets  of  three.  Many  crystals  also 
shew  a  small  plane  (£  [2  P  2]  in  Naumann's  notation),  usually  rhombic  or 
rhomboidal  in  shape  and  often  striated,  on  alternate  angles  of  the  prism- 
pyramid.  Although  normally  colourless,  Quartz  very  commonly  presents 
various  shades  of  violet,  pink,  red,  yellow,  green,  brown,  £c.,  and  some  rock- 
varieties  are  dark-grey  or  black.  The  crystallized  examples  comprise  Rock- 
crystal,  Amethyst,  Cairngorm,  Smoky  Quartz,  &c.  Massive,  crystalline,  or 
sub-crystalline  varieties  include  Common  Quartz,  Rose  Quartz,  Prase,  some 
kinds  of  Jasper,  &c.  (many  of  these  containing  intermixed  iron-oxide,  chlorite, 
actynolite,  or  other  foreign  matters) ;  whilst  the  nodular,  stalactitic,  and 
amygdaloidal  examples,  composed  largely  of  amorphous  silica,  comprise  Cal- 
cedony,  Carnelian,  Cat's-Eye,  Chrysoprase  (coloured  apple-green  by  NiO), 
Agate,  Flint,  Blood-stone,  and  other  varieties. 

Opal  consists  of  amorphous  silica,  and  most,  if  not  all,  examples  yield  a 
certain  amount  of  water  on  ignition.  It  occurs  only  in  nodular,  amygdaloidal 
or  botryoidal  masses,  or  in  small  veins,  essentially  in  trappean  or  volcanic 
rocks.  Its  sp.  gr.  rarely  exceeds  2'0  or  2 '2,  and  its  degree  of  hardness  is 
always  below  that  of  ordinary  quartz.  In  powder,  it  is  dissolved  more  or  less 
readily  by  a  hot  solution  of  caustic  potash  or  soda.  The  noble  opal  is  beautifully 
iridescent ;  but  ordinary  varieties,  comprising  the  so-called  semi-opals,  milk- 


MINERAL  TABLES  : — XXIV.  209 

opals,  wood-opals,  &c.,  much  resemble  calcedonic  varieties  of  quartz,  and  are 
usually  opaque-white,  brown,  red,  yellow,  or  grey  in  colour.  Hyalite  is  a 
transparent  glassy  variety  in  small  botryoidal  masses  on  lava.  As  regards 
these  and  other  varieties  of  Opal  (see  the  Table),  the  more  distinctive  characters 
are  as  follows:  low  sp.  gr.  (r5-2'5);  amorphous  structure;  infusibility  ; 
presence  of  water  ;  solubility  (or  partial  solubility  if  mixed  with  quartz)  in 
caustic  potash. 

Topaz  is  apparently  an  aluminous  silicate  combined  with  a  fluoride.  It  con- 
tains 17£  per  cent,  of  fluorine,  but  gives  a  very  feeble  indication  of  that  substance 
with  sulphuric  acid,  owing  to  its  general  insolubility.  If  fused,  however,  with 
some  previously  fused  phosphor-salt  in  a  piece  of  open  tube — the  flame  being 
directed  into  the  tube  upon  the  assay — the  glass  becomes  corroded.  Topaz 
occurs  commonly  in  crystals,  more  rarely  in  small  rolled  pebbles  (distinguished 
from  quartz  pebbles  by  their  ready  cleavage  and  higher  sp.  gr. ),  and  occasionally 
in  opaque,  granular  or  columnar  masses  (Pycnite,  Physalite)  of  a  reddish- white 
or  yellowish  colour.  In  all,  the  hardness  exceeds  that  of  quartz,  and  the  sp. 
gr.  is  comparatively  high  (3 '5-3*6).  The  crystals  belong  to  the  Rhombic 
System,  and  are  invariably  prismatic  in  aspect,  with  V  :  V  124°  17',  and 
V2:V293°ir.  They  are  of  three  general  types:  (1),  the  Brazilian  type, 
essentially  of  a  wine-yellow  colour,  presenting  several  vertical  prisms  (some 
of  which,  however,  are  merely  denoted  by  vertical  striae),  terminated  by 
four  planes  of  a  rhombic  pyramid  measuring  141°  over  front  polar  edge,  and 
101°  40'  over  side  edge,  the  basal  plane  wanting  ;  (2)  the  Siberian  type,  essen- 
tially of  a  pale  blueish-green  colour,  resembling  that  of  ordinary  beryls,  and 
consisting  of  vertical  forms  with  two  more  or  less  largely  developed  side-polars 

or  brachydomes,  2  P,  measuring  92°  42'  over  the  summit — the  basal  plane 
being  either  absent  or  of  comparatively  small  size,  and  other  planes,  if  present, 
being  also  but  slightly  developed  ;  and  (3)  the  Saxon  type,  of  very  pale-yellow 
colour,  or  nearly  colourless,  characterized  essentially  by  its  largely-developed 
basal  plane,  with  polar  planes  (of  several  forms)  subordinately  present.  These 
definitions  hold  good  in  the  main,  but  crystals  of  intermediate  type  occasionally 
occur. 

Beryl,  a  silicate  of  alumina  and  glucina,  occurs  only  in  crystals  or  crystalline 
columnar  aggregations.  The  species  consists  of  two  leading  varieties,  com- 
prising the  Beryl  proper  and  the  Emerald.  In  both,  the  crystals  as  a  rule  are 
simple  hexagonal  prisms  with  largely-developed  basal  plane  ;  but  in  some  the 
basal  edges  or  angles  (or  both)  are  replaced  by  a  border  of  narrow  pyramidal 
planes  ;  and  occasionally  the  vertical  edges  are  replaced  by  the  prism  V2.  In 
Beryl  the  vertical  planes  are  generally  longitudinally  striated  by  an  oscillation 
between  the  two  prisms,  and  crystals  are  thus  often  rounded  or  rendered  more 
or  less  cylindrical.  The  colour  is  usually  greenish-white  or  some  pale  shade 
of  green,  greenish-blue  or  yellow,  and  crystals  often  occur  of  large  size.  In 
the  Emerald  the  prism-planes  are  generally  smooth,  and  the  colour  is  emerald- 
green,  derived  from  the  presence  of  a  very  small  amount  of  sesquioxide  of 
Chromium.  In  both  varieties  the  hardness  exceeds  that  of  quartz,  and  the 
average  sp.  gr.  equals  2 '7.  In  the  blowpipe-flame,  fine  splinters  lose  their 
15 


21(5  BLOWPIPE   PRACTICE. 

colour,  become  opaque,  and  vitrify  at  the  extreme  point ;  but,  practically,  the; 
mineral  may  be  regarded  as  infusible. 

Cyanite  or  Kyanite,  also  known  as  Disthene,  occurs  commonly  in  long, 
bladed  or  broadly-fibrous  aggregations  of  a  mixed  blue  and  white  colour,  but 
occasionally  of  a  red,  grey  or  other  tint,  and  also  in  examples  of  narrow-fibrous 
structure.  The  flat  surfaces  are  readily  scratched  by  a  knife,  whilst  the  edges 
scratch  glass  strongly.  The  Crystal- System  is  Anorthic,  but  crystals  as  a 
rule  are  imperfectly  formed.  They  consist  of  long  narrow  prisms,  with  indis- 
tinct terminal  planes  in  most  examples.  The  blue- white  colour,  bladed 
structure,  perfect  infusibility,  and  assumption  of  a  blue  colour  by  ignition 
with  nitrate  of  cobalt,  are  the  leading  distinctive  characters.  In  examples 
from  St.  Gothard,  frequently  seen  in  collections,  Cyanite  crystals  in  mica  slate 
are  closely  conjoined  with  long  narrow  prisms  of  dark-red  Staurolite. 

Andalusiteis  identical  with  Cyanite  in  composition  (A1203,  SiO2),  but  presents 
a  very  different  aspect,  and  crystallizes  in  the  Rhombic  System.  It  is  generally 
in  granular  masses,  or  in  rectangular  prisms,  of  a  peach-blossom  red  or  greyish 
eolour.  The  crystals  are  often  large  and  coarsely  formed.  In  blowpipe 
characters,  it  resembles  Cyanite. 

Staurolite  may  in  general  be  recognized  easily  by  its  dark-brown,  brownish- 
black,  or  dark-red  colour,  its  very  common  cruciform  crystallization,  and  its 
infusibility.  Simple  crystals  however  are  also  of  frequent  occurrence.  These 
consist  invariably  of  an  obtuse  rhombic  prism,  with  V :  V  129°  20',  truncated 
(sometimes  deeply,  sometimes  very  slightly)  on  the  side  or  acute  vertical 
edges,  so  as  to  form  a  six-sided  prism,  and  carrying  generally,  in  addition,  a 
front-polar  form,  P,  mostly  of  small  size.  The  basal  plane  has  generally  a- 
rough  surface,  and  many  crystals  are  rough  and  dull  throughout.  These 
crystals  occur  very  commonly  in  cruciform  twins,  in  some  of  which  the 
crystals  cross  each  other  at  right  angles,  and  in  others  obliquely.  The  prism- 
apgle  V  :  V  appears  to  vary  from  about  128°  4(X  to  129°  30'.  B :  P  averages 
124°  30'  to  125°  30'. 

Chrysolite  proper  is  commonly  of  a  pale-yellow  or  yellowish -green  colour  j 
but  in  the  variety  known  as  Olivine,  the  colour  is  dark-green,  or  brownish- 
yellow,  or  occasionally  red,  and  this  variety  occurs  chiefly  in  small  granular, 
more  or  less  transparent  masses,  imbedded  in  basalt  and  lava.  Chrysolite, 
proper,  occurs  in  small  crystals  and  crystalline  grains,  and  is  normally  a  pure 
silicate  of  magnesia,  whilst  in  Olivine,  much  of  the  MgO  is  replaced  by  FeO. 
The  crystals  are  Rhombic,  and  are  mostly  combinations  of  the  vertical  forms 

V,  V,  V2r  and  V ;  the  polar  forms  P,  P,  and  2P ;  and  the  base  B,  the  latter 
sometimes  failing.  V  :  V '  =  130P  2' ;  V2:  V2;  94°  2' ;  P:  P  over  front  edge, 

139°  54' ;  over  side  edge,  85°  16'  -T  F:  B,  128°  17' ;  2P :  2P,  over  B  or  summit,. 
80°  53'.  Both  varieties  are  decomposed,  in  powder,  by  hydrochloric  acid,  and 
also  by  sulphuric  acid,  the  silica  separating  in  (usually)  a  gelatinous  condition. 
Normal  examples  are  infusible,  but  very  ferruginous  varieties  (hyalosideriter 
&c.)  often  vitrify  on  thin  edges.  The  leading  characters  of  Qlivine  are  its 


MINERAL  TABLES: — xxiv.  211 

peculiar  greenish-yellow  or  green  colour,  its  occurrence  in  traps  and  lavas,  its 
general  infusibility,  and  its  gelatinization  in  acids. 

Chondrodite,  essentially  a  magnesian  fluo-silicate,  occurs  commonly  in  the 
form  of  small  granular  masses,  chiefly  of  a  yellow  colour,  imbedded  in 
crystalline  limestone  ;  but  green,  yellowish-red,  and  other-coloured  varieties 
are  also  known.  It  occurs  also,  though  less  commonly,  in  small  crystals  with 
numerous  planes,  belonging  to  the  Clino-Rhombic  System.  Humite  and  Clino- 
Humite  (chiefly  from  Vesuvius)  are  closely  similar  in  composition  and  general 
physical  characters,  but  the  first  is  Rhombic  in  crystallization,  and  the  latter 
presents  different  angular  values.'  All  give  a  marked  fluorine  reaction  by 
treatment  in  powder  with  hot  sulphuric  acid.  For  other  characters,  see  the 
Table. 

Tourmaline  may  in  general  be  recognized  without  difficulty  by  the  essentially 
triangular  character  of  its  crystals  and  crystalline  needles,  as  seen  more 
especially  on  the  transverse  fracture.  The  crystals  are  generally  nine-sided 

V 

prisms,  consisting  of  three  planes  of  a  hemi-hexagonal  prism  g",  combined  with 

the  second  hexagonal  prism  V2,  the  latter  occurring  as  a  bevelment  on  the 
vertical  edges  of  the  half -form.  These  prisms,  when  perfect,  are  terminated 
by  rhombohedron-planes,  with  or  without  a  basal  plane,  or  frequently  by 
rhombohedron-planes  at  one  extremity,  and  by  a  single  large  basal  plane  or 
dissimilar  forms  at  the  other.  The  rhombohedron-planes  belong  chiefly  to  the 
forms  R,  -  £R,  -  2R,  in  which  the  angle  over  polar  edges  equals,  respectively, 
133°  10'  or  thereabout,  155°,  and  103°.  Black  varieties  (known  as  Schorl)  and 
most  dark-brown  varieties  are  easily  fusible  (see  TABLE  XXVI.),  but  the  red, 
green,  blue,  clear-brown,  and  colourless  examples  are  either  infusible,  or 
fusible  only  on  the  thinnest  edges.  Some  crystals  are  red  internally  and  green 
externally,  or  present  different  colours  at  the  extremities  ;  and  nearly  all  the 
clear  exainples  are  transparent  when  viewed  across  the  prism,  and  opaque 
longitudinally.  All,  moreover,  exhibit  electrical  polarity  when  heated.  * 

lolite,  known  also  as  Dichroite  and  Cordierite,  is  commonly  in  the  form  of 
small,  granular,  vitreous  or  resino-vitreous  masses,  imbedded  in  granitic  and 
crystalline  metamorphic  rocks  ;  but  is  found  at  some  localities  in  distinct 
crystals,  and  occasionally  in  the  form  of  small  rolled  pebbles  in  alluvial  deposits. 
The  colour  is  mostly  dark-blue  or  pale-blue  by  reflected  light,  and  brownish 
or  yellowish  by  transmitted  light,  whence  the  name  Dichroite.  Some  varieties, 
however,  are  colourless,  grey,  or  blueish-brown.  The  crystals  belong  to  the 
Rhombic  System,  but  have  in  general  a  pseudo-hexagonal  aspect :  a  common 

combination  consisting  of  the  forms  V,  V,  P,  P,  and  B ;  with  V:  V  119°  1(X; 
B :  P  150°  49'.  Fine  splinters  melt  at  the  extreme  point,  but  practically  the 


*  This  may  be  shewn  by  suspending  a  crystal  from  the  ring  of  the  blowpipe-lamp,  or  other 
'•.onvenient  support,  by  means  of  a  piece  of  thin  silk-thread  tied  round  the  centre  of  the  crystal. 
The  latter  is  heated  carefully  in  a  small  platinum  or  porcelain  capsule,  care  being  taken  not  to 
burn  the  thread,  over  a  spirit-flame  or  Bunsen-burner.  On  the  capsule  being  removed,  one 
^.nd  of  the  prism  will  be  attracted,  and  the  other  end  repelled,  by  a  glass  stirring-rod  or  stick 
>f  sealing-wax  rubbed  previously  for  a  few  seconds  on  the  coat-sleeve. 


212  BLOWPIPE    PRACTICE. 

species  may  be  placed  among  the  infusible  silicates.  From  blue  Corundum 
(Sapphire),  and  from  Sapphirine  and  blue  Spinel,  it  is  readily  distinguished 
by  its  low  sp.  gr.  (2  "6).  From  blue  Tourmaline  (Indigolite),  also,  by  lower 
sp.  gr.,  and  by  not  becoming  electric  when  heated  ;  and  from  Quartz,  by 
forming,  BB  with  carb.  soda,  a  slaggy  semi-fused  mass  in  place  of  a  clear 
glass.  Many  examples  of  lolite  are  partially  altered  or  decomposed,  and 
these  give  traces  of  water  in  the  bulb-tube. 

Leucite  is  readily  distinguished,  as  a  rule,  by  its  occurence  in  small  rounded 
grains  or  crystals  of  a  white,  grey,  or  pale-yellowish  tint,  in  lava.  The  crystals 
closely  resemble  the  trapezohedron  2-2  of  the  Regular  System,  but  have  been 
shewn  by  Von  Eath  to  be  really  Tetragonal — at  least  as  regards  most 
examples,  if  not  all.  Many  crystals  contain  minute  needles  and  scales  of 
augite,  magnetite,  &c.,  scattered  through  their  substance.  In  powder,  leucite 
is  slowly  decomposed  by  hot  hydrochloric  acid.  The  solution,  rendered  pasty 
by  partial  evaporation,  shews  the  red  K-line  in  the  spectroscope  if  held  011  a 
clean  platinum  wire  for  a  few  seconds  in  the  outer  edge  of  a  Bunsen-flame. 
The  K-line  is  rendered  visible  also  by  igniting  some  of  the  powder  on  a  loop 
of  platinum  wire,  and  then  dipping  it  into  some  carbonate  of  soda  or  powdered 
fluor-spar,  and  again  exposing  to  the  flame.  The  glare  from  the  sodium 
spectrum  may  be  entirely  cut  off  by  the  intervention  of  a  piece  of  deep-blue 
glass. 

Orthoclase-;  Albite.  These  species  belong  properly  to  Table  XXVI,  and 
their  crystallographic  and  other  characters  are  there  described.  In  general, 
they  form  cleavable  masses  of  a  white,  flesh-red,  bright-red,  grey,  pale-yellowish 
or  clear-green  colour  ;  or  occur  in  crystals  of  a  more  gr  less  flattened  aspect, 
often  twinned  (see  Note  to  TABLE  XXVI.).  In  Orthoclase  the  principal  clea- 
vage planes  meet  at  right  angles  ;  in  Albite,  at  angles  of  93°  36'  and  86°  24', 
and  one  of  the  cleavage  planes  in  the  latter  species  generally  shews  a  delicate 
striation,  best  seen  under  the  magnifying  glass.  Orthoclase,  treated  in  powder 
with  carb.  soda  (as  described  under  Leucite,  above)  shews  very  distinctly  the 
red  K-line  in  the  spectroscope.* 

*  This  test  for  the  presence  of  potash  in  Orthoclase,  so  far  at  least  as  regards  the  use  of  carb. 
soda,  was  first  described  by  Bunsen.  If  the  mineral,  in  powder,  be  fused  with  fluor-spar  the 
red  K-line  comes  out,  I  find,  still  more  distinctly ;  and  many  examples,  when  thus  treated, 
shew  the  Li-line  as  well.  By  the  intervention  of  a  piece  of  blue  glass  the  Ca-lines  (from  the 
fluor-spar)  and  the  Li-line  become  obliterated,  and  only  the  K-line  remains  visible.  The  latter 
is  also  brought  out  in  most  if  not  in  all  cases  by  simply  moistening  the  test-matter,  after 
ignition,  with  hydrochloric  acid . 


[213] 


TABLE-    XXV. 

[Lustre  non-metallic  (in  some  cases  pseudo-metallic).  Slowly  or  incompletely 
dissolved  BB  by  phosphor-salt.  Infusible,  or  fusible  on  thin  edges  only. 
Hardness  insufficient  to  scratch  ordinary  window-glass.  |L  V;i,*Vv 

*?•     v%yV- ' 
A. — Occurring  in  micaceous  or  foliated  masses  or  crystals, 

the  foliae  elastic  or  flexible,  and  easily  separable  by 
the  finger-nail. 

Ai.—  FOLLE  DISTINCTLY  ELASTIC. 

MUSCOVITE  (Potash  Mica) :  Essentially  K2O  9,  APO3  35,  Si 
with  small  amounts  of  Fe2O3,  H20,  Fluorine,  &c.  Rhombic  or 
Rhombic  (?),  but  crystals  hexagonal  in  aspect.  Optically  biaxial, 
with  large  angle  of  divergence.  Structure  thin-foliated  or  scaly,  the 
folise  easily  separable.  White,  brown,  black,  green,  &c.,  with  metallic- 
pearly  lustre  on  cleavage-plane ;  flexible  and  elastic  in  thin  pieces ; 
H  2-0-3-0;  G  2-7-3-1.  BB,  exfoliates,  and  melts  readily  on  the 
edges  (if  in  the  form  of  a  thin  scale)  into  a  greyish- white  enamel.* 
In  acids,  insoluble.  Fuchsite  is  a  more  or  less  deep -green  chromi- 
ferous  variety,  in  fine-scaly  aggregations.  Damourite  and  Margarodite 
are  hydrated  micaceous  minerals,  apparently  derived  from  Muscovite. 
See  TABLE  XXV II.  Roscoelite  is  a  Vanadiu  m-mica  (in  small  greenish- 
brown  or  green,  radiately  arranged  foliae  of  metallic-pearly  lustre) 
from  Eldorado  Co.,  California. 

PHLOGOPITE  (Potassic-Magnesian  Mica)  :  K2O  12-75,  MgO  32-55, 
APO3  13-95,  SiO2  40-75,  with  small  amounts  of  H20,  F,  &c.  Rhombic 
(optically  biaxial),  but  essentially  hexagonal  in  aspect ;  thin-foliated, 
or  scaly ;  chiefly  yellowish-brown,  with  golden,  metallic-pearly  lustre 
on  cleavage-face;  H  2 -5-3-0 ;  G  2-75-2-90;  BB,  whitens,  and  melts 
on  thin  edges  into  a  greyish-white  enamel.  In  powder  decomposed 
by  sulphuric  acid,  the  silica  separating  in  colourless  scales.  Common 
in  crystalline  limestones.! 

BIOTITE  (Potassic-Ferromagnesian  Mica) :  Closely  resembles  Phlo- 
gopite  in  composition  and  general  characters,  but  usually  of  dark 
colour — green,  black,  or  brown ;  optically  uniaxial,  and  of  assumed 

*  The  Micas  (Muscovite,  Phlogopite,  Biotite  and  other  representatives,  Lepidolite  excepted), 
are  always  placed  among  the  infmible  species,  in  works  on  Determinative  Mineralogy.  As  a 
rule,  however,  all  melt  more  or  less  readily  on  the  edges  when  tested  in  the  form  of  a  thin 
scale.  In  the  spectroscope,  all  shew  the  red  K-line,  and  many  the  Li-liue  also,  either  per  set 
or  when  moistened,  after  ignition,  with  HC1  acid. 

f  This  species  is  present  iu  great  abundance  in  most  of  the  apatite  deposits  of  Canada. 


214  BLOWPIPE    PRACTICE. 

Hexagonal  crystallization.  Fusible  on  edges  into  a  black  or  dark 
enamel.  Decomposed  by  sulphuric  acid.  Commonly  found  in  vol- 
canic and  trappean  rocks,  but  many  volcanic  micas  are  optically 
biaxial. 

A3.—  FOLLE  FLEXIBLE  BUT  NOT  ELASTIC. 

f  Yield  water  by  ignition  in  bulb-tube. 

CHLORITE  (Pennine)  :  MgO  13  to  27,  FeO  15  to  30,  APO3  19  to 
23,  SiO2  25  to  28,  H2O  9  to  12.  Hexag.  or  Hemi-Hex.  (crystals 
mostly  tabular),  but  commonly  in  foliated  and  scaly  examples  of  a 
dark  or  rich  green  colour ;' flexible  in  thin  pieces;  H  1'0-1'S;  G 
2-65-2-95.  Fusible  on  thin  edges  into  a  yellowish-grey  or  dark  and 
often  magnetic  glass.  Decomposed  by  sulphuric  acid.  Metachlorite, 
Prochlorite,  A  phrosiderite  and  Tabergite,  are  closely  related  chloritic 
substances-.  The  latter  occurs  in  coarse,  bluish-green,  foliated  masses. 

K^EMMERERITE  :  A  chromiferous  chlorite  of  a  red  or  violet-red 
colour,  or  green  by  reflected,  and  red  by  transmitted  light.  Mostly 
in  hexagonal  pyramids  and  prisms  of  foliated  structure. 

BIPIDOLITE  (Clinochlore)  :  Clino-Rhoinbic  in  crystallization,  but 
identical  in  general  characters  and  composition  with  Chlorite  proper. 
Epichlorite,  Korundophyllite,  Helminthite,  are  varieties  or  closely 
related.  Pyrosclerite  is  a  chromiferous  variety  from  Elba.  Delessite 
is  an  essentially  ferruginous  chlorite,  allied  to  this  or  the  preceding 
species,  of  frequent  occurrence  in  amygdaloidal  traps. 

PYROPHYLLITE  (Foliated  Kaolin)  :  APO3,  SiO2,  H2O,  with  traces 
of  MgO,  &c.  Essentially  in  radio- folia  ted  examples  of  a  clear  green 
or  greenish-white  colour,  and  somewhat  pearly  lustre ;  flexible  in 
thin  pieces;  H  I'O;  G  2-75-2-95.  BB,  exfoliates  and  curls  up,  but 
remains  unfused,  or  vitrifies  slightly  on  thinnest  edges  only.  With 
Co-solution  assumes  a  fine  blue  colour.  Talcosite,  from  Victoria,  ih 
a  closely  related  substance,  passing  into  Kaolin  proper. 

f  f  No  water -,  or  traces  only,  in  bulb-tube. 

TALC:  Essential  composition,  MgO  31-7,  SiO2  63-5,  H2O  4-8,  but 
the  H2O  is  not  driven  off  by  moderate  ignition,  and  is  thus  regarded 
as  basic.  Occurs  commonly  in  six-sided  tabular  crystals  and  foliated 
masses  of  a  pearly-white,  greenish- white,  clear-green,  or  greenish- 
grey  colour.  H  TO;  G  2-67-2  80.  BB,  exfoliates,  becomes  opaque- 
white,  and  melts  on  thin  edges,  but  less  easily  than  mica.  With 
Co-solution,  becomes  pale-red.  Insoluble  in  acids. 


MINERAL  TABLES  I — XXV.  215 

33, — Occurring  in  distinctly  schistose  or  foliated  examples,  but 
the  component  folise  more  or  less  brittle,  not  flexible. 

Bi.— YIELD  WATER  BY  IGNITION  IN  BULB-TUBE.* 

MARGARITE  (Pearl  Mica)  :  CaO,  APO3,  SiO2,  H2O,  with  small 
amounts  of  K2O,  Na2O,  Li2O,  MgO,  F,  &c.  Rhombic  (?)  .;  mostly  in 
six-sided  tables  and  lamellar  masses  of  a  pearly-white,  pale-green, 
reddish  or  greyish  colour;  the  lamellae  more  or  less  brittle.  H 
3-5-4-0;  G  2-95-3-10.  BB,  melts  on  the  edges,  often  with  slight 
intumescence.  Scarcely  attacked  by  acids.  In  spectroscope,  after 
ignition  and  moistening  with  HC1  acid,  shews  momentary  red  and 
green  Ga-lines,  and,  in  most  examples,  red  K  and  Li  lines,  also. 
Emeryllite,  Euphyllite,  Diphanite  and  Gilbertite,  are  identical  or 
/closely  related.  Euphyllite,  however,  is  decomposed  by  sulphuric  acid. 

ANTIGORITE  (A  slaty  Serpentine) :  MgO  36  to  37,  FeO  6  to  7, 
SiO2  41  to  43,  H2O  11-5  to  12-5,  with  traces  of  APO3,  &c.  In 
schistose  masses  of  a  dark  green  or  greenish-brown  colour;  H  2*5  ; 
G  2-62.  Fusible  on  thin  edges.  Slowly  decomposed  by  sulphuric 
acid. 

SCHILLER  SPAR  (Bastite).  Probably  an  altered  Bronzite  :  Con- 
tains MgO,  FeO,  SiO2,  with  about  12  per  cent.  H2O,  and  small 
amounts  of  K2O,  CaO,  Cr2O3,  APO3,  &c.  In  schistose  or  foliated 
masses  of  a  dark-green  colour,  with  yellowish-brown  reflections  on 
the  cleavage  surfaces.  H  3-5-4-0;  G  2'6-28;  BB,  melts  on  the 
edges  only;  becomes  brown  and  sometimes  magnetic  -after  ignition. 
Decomposed  by  sulphuric  acid. 

PICROPHYLL  :  A  hydrated  magnesian  silicate  occurring  in  sub- 
foliated  or  coarse-fibrous  examples  of  a  greenish-grey  colour;  H  2 -5^ 
G  2-73.  Fusible  on  thin  edges.  Regarded  as  an  altered  Pyroxene. 

CHLOROPHYLLITE  :  Contains  MgO,  MnO,  APO3,  Fe2O3,  SiO2,  HX). 
In  foliated  masses  or  coarse  indistinctly  formed  crystals  of  a  green 
or  brownish  colour.  H  about  3'0 ;  G  about  2-7.  Fusible  on  thin 
«dges  only.  Scarcely  attacked  by  aoids.  Probably,  in  part,  an 
altered  lolite. 

GROPPITE:  Contains  K2O,  CaO,  MgO,  APO3,  Fe2O8,  SiO2,  H2O 
{7  per  cent.).  In  foliated  or  scaly  masses  of  a  rose- red  or  brownish- 

*  Few,  if  any,  of  the  minerals  belonging  to  this  section  can  be  regarded  as  true  species.  A>- 
a  rule,  they  consist  of  altered  products  of  more  or  less  unstable  composition,  and  their  deter- 
jniuative  characters  are  commonly  ill-defined.  This  remark  applies,  with  few  exceptions,  ti> 
•the  representatives  of  the  present  Table,  generally. 


216  BLOWPIPE    PRACTICE. 

red  colour,  the  folise  brittle;  H  2-5-3-0;  G  2-73.     BB,  whitens,  and 
vitrifies  on  thin  edges. 

B*  —  ANHYDROUS  SPECIES  :  NO  WATER,  OR  TRACES  ONLY,  EVOLVED  IN 
BULB-TUBE. 

BRONZITE  (Foliated  Enstatite)  :  Contains  MgO,  EeO,  SiO2.  Com- 
monly in  schistose  or  foliated  masses  of  a  dark-brown  or  dark-green 
colour,  with  pseudo-metallic  bronze-like  lustre,  and  very  perfect 
cleavage  in  one  direction.  H  4-0-5-0 ;  G  2-9-3-5.  Fusible  on 
thinnest  edges  only.  Not  attacked  by  acids. 

ANTHOPHYLLITE  :  MgO  27-8,  FeO  16-7,  SiO2  55-5.  Rhombic, 
but  essentially  in  thin-lamellar  and  fibrous  masses,  with  tolerably 
easy  cleavage  in  three  directions;  yellowish-brown,  greenish-grey, 
bronze-green,  with  somewhat  metallic-pearly  lustre.  H  5-0;  G  3-2. 
BB,  vitrifies  only  on  thinnest  edges  into  a  black  magnetic  enamel : 
practically,  infusible.  Very  slightly  attacked  by  acids.* 

CLINTONITE  :  Composed  essentially  of  CaO,  MgO,  APO3,  SiO2,  with 
traces  of  H2O.  Chiefly  in  hexagonal  tables  of  a  brown  or  yellow 
colour,  with  metallic-pearly  lustre;  H  5-0;  G  3-0-3*2.  Practically 
infusible.  Decomposed  by  hydrochloric  acid.  Xanthophyllite  (in 
yellow  radiating  lamellae  on  certain  talcose  schists),  and  Brandisite 
(in  dark-green  tabular  crystals,  weathering  brownish),  are  apparently 
related  compounds,  but  are  only  partially  attacked  by  hydrochloric 
acid.  In  Clintonite  and  in  these  related  silicates  the  silica  is  under 
20  or  21  per  cent.  Ignited  and  moistened  with  HC1  acid,  all  shew 
in  the  spectroscope  red  and  green  Ca-lines  in  momentary  flashes. 

C. — Occurring  in  crystals  or  in  granular,  fibrous,  compact,  or 
other  non-micaceous  examples.  Streak-powder  colour- 
less, pale-green,  or  lightly- tinted,— not  black. 

CX— YIELDING  WATER  BY  IGNITION  IN  BULB-TUBE. 

f  Form  with  borax,  ££,  a  deeply  coloured  glass. 

(Ou  reaction)* 

DIOPTASE  :  CuO  50-44,  SiO'  38-12,  H2O  11-44.  In  emerald-green 
crystals — hexagonal  prisms  with  rhombohedral  summit-planes — suffi- 

*  In  ordinary  examples,  Bronzite  and  Anthophyllite  can  rarely  be  separately  distinguished. 
The  first  is  regarded  as  a  Rhombic  representative  of  the  Pyroxene  series,  and  the  latter  as  a 
Rhombic  Amphibole ;  but  the  characteristic  pyroxene  and  amphibole  angles  (87°  6'  and  124°  30% 
or  angles  approaching  these,  are  rarely  determinable.  Hypersthene  is  a  very  ferruginous  and, 
comparatively  hard.  Bronzite,  distinctly  fusible.  See  TABLE  XXYI. 


MINERAL    TABLES  : XXV.  217 

ciently  hard  (5-0-5-5)  to  scratch  glass  slightly  :  See  TABLE  XXIY. 
G  3-3.  BB,  decrepitates  and  blackens,  but  does  not  fuse.  With 
carb.  soda,  easily  reduced.  Gelatinizes  in  heated  hydrochloric  acid. 
A  rare  species,  in  crystalline  limestone  from  the  Kirghis  Steppes  of 
Western  Siberia. 

CHRYSOCOLLA  (including  Kupferblau,  &c.) :  Composition  somewhat 
variable,  but  essentially  CuO  45-27,  SiO2  34-21,  H2O  20-52.  In 
amorphous  and  botryoidal  masses,  coatings  on  copper  ores,  and 
occasionally  in  pseudomorphs.  Colour,  green,  greenish-blue,  bright- 
blue;  brownish  or  black  from  presence  of  Fe2O3,  MnO2,  <fec.;  H 
2-0-5-0;  G  2-0-2-6.  BB,  blackens,  but  does  not  fuse.  On  charcoal 
with  carb.  soda,  reduced  to  metallic  Cu.  Decomposed  with  separation 
of  silica  (but  as  a  rule  without  perfect  gelatinization)  by  hydrochloric 
acid.  Demidowite  is  a  Chrysocolla  mixed  with  copper  phosphate. 
Asperolite  a  variety  with  27  per  cent.  H2O.  Other  varieties  are 
mixed  with  copper  carbonate,  opalized  silica,  <fec. 

ALLOPHANE  (Cupreous  varieties)  :  A1203,  SiO2,  H20  (35  to  36  per 
cent.),  mixed  with  copper  silicate.  In  amorphous,  stalactitic  and 
botryoidal  examples,  coatings,  &c.,  of  a  light-blue,  green,  red,  or 
brownish-yellow  colour.  H  about  3-0 ;  G  about  2-0.  BB,  blackens, 
and  often  swells  up  slightly,  but  does  not  fuse.  In  HC1  acid, 
gelatinizes. 

(Ni  reaction:  page  43). 

RJETTISITE:  NiO,  SiO*,  H2O  (11  per  cent.),  mixed  with  Fe20», 
copper-phosphate,  cobalt-arseniate,  <fec.  Amorphous,  incrusting; 
green  of  various  shades;  H  2-0-2-5  ;  G  2-3-2-4. 

GENTHITE  (Nickel-Gymnite) :  NiO,  MgO,  SiO2,  H2O  (19  per  cent.). 
In  green  and  greenish-yellow  coatings  on  some  examples  of  Chromic 
Iron  Ore,  and  occasionally  in  soft  sub-earthy  masses.  H  2*0-4-0; 
G  about  2-4.  BB,  infusible,  blackens. 

PIMELITE:  MgO,  NiO,  A1203,  SiO2,  H2O  (21  per  cent.).  In 
earthy  masses,  coatings,  &c.,  of  an  apple-green  colour.  H  1-0-2-5  ; 
G  2-3  (to  2-71).  BB,  blackens,  and  vitrifies  on  thin  edges.  Alipite 
and  Chrysoprase-Earth  are  identical  or  closely  related  compounds. 

(Fe  reaction). 

ANTHOPHYLLITE  :  In  yellowish-brown,  or  greenish  metallic-pearly 
examples  of  lamellar  or  fibrous  structure.  Some  examples  only  yield 
traces  of  water  on  ignition,  See  B2,  above. 


218  BLOWPIPE    PRACTICE. 

HISINGERITE  (Thraulite) :  FeO,  Fe203,  SiO2,  H2O  (10  to  20  or  22 
per  cent.),  with  small  amounts  of  MgO,  APO3,  &c.  In  earthy  and 
nodular  masses  of  a  pitch-black  or  brownish-black  colour,  with 
brownish  streak.  H  3-0-4-0;  G  2 -6-3-1.  BB,  becomes  magnetic, 
and  vitrifies  on  the  edges,  or  in  some  examples  melts  into  a  steel-grey 
magnetic  globule*  (see  TABLE  XXVII.).  Decomposed  by  HC1  acid 
with  separation  of  slimy  silica. 

NONTRONITE  :  Essential  components  Fe203,  SiO2,  H2O  (2 1  to  2f> 
per  cent.),  but  small  amounts  of  APO3,  CaO,  &c.,  are  also  generally 
present.  In  earthy  and  nodular  masses  of  a  yellow,  green,  greenish- 
white  or  brownish  colour;  H  1 -0-1-5;  G  2-0-2-4.  BB,  infusible,  or 
fusible  on  the  edges  only,  but  becomes  magnetic.  Pinguite  and 
Gramenite  are  identical  or  closely  related.  Chloropal  (Unghwarite) 
is  also  very  similar  in  general  characters  and  composition,  but  is 
somewhat  harder,  probably  from  admixture  with  opalized  SiO2. 

(Or  reaction:  see  page  48). 

WOLCHONSKOITE  :  Cr2O3,  Fe2O  ,  SiO2,-  H2O  (about  20  or  21  per- 
cent.), with  small  amounts  of  MgO,  MnO,  APO3,  &c.  In  earthy 
and  nodular  masses  of  a  grass-green  or  blackish-green  colour ;  H 
1-5-2-5;  G  2-2-2-3.  BB,  practically  infusible;  gelatinizing  in  HC1 
acid. 

MILOSCHIN  (Serbian) :  APO3,  Ci^O3  (under  4  per  cent.),  SiO2,  IPO 
(about  23  per  cent.).  In  blue  or  blue-green,  earthy  and  amorphous 
masses;  H  1 -0-2-0;  G  2-1-2-2;  adheres  to  the  tongue.  BB,  infusible. 
Partially  decomposed  by  hydrochloric  acid. 

f  f  Form  BB  with  borax  an  uncoloured  or  lightly-tinted  glass. 
(The  saturated  borax-glass  becomes  opaque-white  on  cooling  or  when  flamtd). 

CERITE:  CeO  (LaO,  DiO)  73-5,  SiO2  20-4,  H2O  6-1.  Chiefly  in 
fine-granular  masses  of  a  red,  brownish,  or  reddish-grey  colour.  H 
5-0-5-5  (scratches  glass  feebly) ;  G  4-9-5-0.  BB,  becomes  dull  yellow, 
but  remains  unfused.  Gelatinizes  in  hydrochloric  acid. 

THORITE  :  ThO2,  SiO2.  H2O.  Heg.  ?  Mostly  in  small  black  masses, 
often  fissured,  and  sometimes  with  reddish  coating ;  streak,  brownish 
or  reddish;  H  about  4-5;  G  4-4-4'7.  BB,  becomes  yellow,  but 

*  L.  H.  Fischer:  Clavis  der  Silicate:  1864.  This  work,  a  Determinative  Grouping  of  the 
Silicates  (containing  many  original  observations),  should  have  been  referred  to  among  the  list 
of  works  oh  Determinative  Mineralogy  at  page  21. 


MINERAL   TABLES  :— XXV.  219 

remains  unfused.  Gelatinizes  in  HC1  acid.  Very  rare  :  commonly 
regarded  as  altered  Orangite. 

ORANGITE:  ThO2,  SiO2,  H2O.  Tetragonal?  Mostly  in  small 
granular  or  sub-foliated  examples  of  a.  reddish-yellow  or  orange-red 
colour;  H  4-5;  G  5 -2-5 -4.  Gelatinizes  in  HC1  acid.  Very  rare; 
accompanies  Thorite  in  the  micaceous  zircon-holding  syenite  of 
Brevig  in  Norway. 

[NOTE. — Most  examples  of  Cerite,  Thorite,  and  Orangite,  when  ignited  and 
moistened  with  hydrochloric  acid,  shew  a  momentary  Ca-spectrum.] 

(A  zinc-sublimate  formed  on  charcoal  by  fusion  with  carb.  soda  and  borax). 

CALAMINE  :  ZnO  67  -5,  SiO2  25,  H2O  7'5.  Crystallization  Rhombic ; 
crystals  mostly  hemimorphic  (with  B  plane  at  one  extremity  only), 
arranged  in  drusy  or  fan-shaped  aggregations,  and  generally  flattened 

o 

from  extension  of  the  side  vertical  or  brachy-pinakoid  faces  V.  The 
species  occurs  also  very  commonly  in  botryoidal,  cavernous,  and 
other  examples ;  colourless,  white,  yellowish,  brown,  green,  light- 
blue ;  H  5'0  (scratches  glass  feebly);  G  3*3-3'5 ;  crystals,  pyro- 
electric.  Infusible,  BB,  or  vitrified  slightly  on  thinnest  edges,  only, 
only.  Gelatinizes  with  hydrochloric  acid.  Ignited  with  Co-solution, 
becomes  green  (or  partly  blue  and  partly  green)  on  cooling. 

(Slowly  attacked  BB  by  borax  ;  the  glass  not  rendered  opaque  by  flaming. 
With  Co-solution,  assume  a  distinct  blue  colour). 

KAOLIN:  APO3  397,  SiO2  46-4,  H2O  13-9.  Chiefly  in  earthy  or 
fine -granular  masses  made  up  in  part  of  microscopic  scales.  White, 
pale-red,  greenish- vvhite ;  H  1-0  or  less;  G  2 -1-2-3  (or  in  some 
varieties  slightly  higher:  2-3-2-6).  Infusible;  decomposed  by  hot 
sulphuric  acid.  Cimolite,  Anauxite,  Pelicanite,  Hunterite,  &c.,  are 
related  aluminous  compounds,  but  contain  a  somewhat  higher  per- 
centage of  silica. 

NACRITE  or  PHOLERITE  :  A  crystalline  or  sub-foliated  Kaolin,  in 
pearly-white  scaly  masses  or  six-sided  tables,  often  in  fan-shaped 
groups.  Composition  and  other  characters  as  in  Kaolin  proper. 

AGALMATOLITE  (Figure  Stone  *  in  part) :  K2O,  APO3,  SiO2,  H20 
(about  5  per  cent.).  White,  pale-grey,  yellowish,  pale-red,  green, 

*  Although  many  of  the  smaller  Chinese  images  are  carved  out  of  this  stone,  a  great  number 
(perhaps  the  greater  number)  consist  of  steatite  or  of  serpentine.  In  these,  the  substance 
blackens  in  the  bulb?tube,  and  assumes  a  flesh-red  colour  after  ignition  \vith  Co-solution. 


220  BLOWPIPE    PRACTICE. 

greenish-white ;  mostly  in  fine-granular  almost  compact  masses,  but 
these  consist  frequently  of  microscopic  scales;  H  2-0-3-0;  G  2-8-2-9. 
BB,  whitens,  and  vitrifies  on  thin  edges.  Decomposed  by  sulphuric 
acid.  Shews  the  red  K-line  very  distinctly  in  spectroscope,  when 
ignited  and  moistened  with  HC1  acid. 

FINITE  :  K2O,  MgO,  FeO,  Fe2O3,  APO3,  SiO2,  H20  (4  to  8  per 
cent.).  In  six-sided  and  twelve-sided,  more  or  less  opaque  crystals, 
of  a  greyish-white,  grey,  brown,  greenish  or  bluish  colour ;  H  2-0-3-5 ; 
G  2 -5-2 -9.  BB,  vitrifies  on  thin  edges  only.  In  spectroscope  shews 
distinctly  the  red  K-line  when  ignited  and  moistened  with  hydro- 
chloric acid.  Apparently  an  altered  lolite.  The  following  sub- 
stances, all  of  which  give  a  K-spectrum,  are  more  or  less  closely 
related:  Pyrargillite  from  Finland  (brown,  brownish -red,  H2O  15-5 
per  cent.) ;  Fahlunite  (dark-brown,  dark-green,  greyish,  H20  8  to  9 
per  cent.);  Weissite  (grey,  brown,  H2O  3  to  5  per  cent.);  Iberite 
from  the  vicinity  of  Toledo  (greyish-green,  in  coarse  six-sided  prisms, 
aq. .5  to  6  per  cent.);  GIESECKITE  (greenish-grey,  aq.  about  6  per 
cent.) ;  Liebenerite  (green,  greyish,  aq.  about  5  per  cent.).  The  two 
latter  are  regarded  as  altered  nepheline ;  the  others  as  altered  iolite. 
In  all,  the  hardness  is  below  4-0,  and  the  sp.  gr.  below  2-9.  Gigan- 
tolite  belongs  to  the  same  series,  but  is  readily  fusible  (see  TABLE 
XXVII). 

ESMARKITE:  MgO,  MnO,  FeO,  Fe20»,  A12O3,  SiO2,  H2O  (5-5  per 
cent.).  This  mineral,  like  those  placed  under  Finite,  above,  is  also 
apparently  an  altered  lolite;  but  it  is  placed  here,  apart,  as  the 
representative  of  a  non-potassic  series.  Occurs  mostly  in  coarse 
twelve-sided  prisms  of  more  or  less  scaly  texture;  grey,  brown, 
greenish,  &c.,  in  colour;  and  dull  and  opaque,  or  practically  so.  H 
3-0-4*0;  G  2-6-2*8;  fusible  on  thin  edges  only.  Praseolite,  Aspasio- 
lite,  and  JBonsdorffite,  are  identical  or  closely  related  substances  of  a 
green  or  greenish-brown  colour,  occurring  mostly  in  six-sided,  eight- 
sided,  or  twelve-sided  prisms,  with  dull  surface  and  rounded  edges. 

HALLOYSITE:  A12O3  35,  SiO2  41,  H2O  24.  Nodular,  earthy; 
greenish  or  greyish-white,  pale  dingy  blue;  H  1-0-2-5;  G  1-9-2-1  ; 
feels  somewhat  greasy,  and  adheres  to  the  tongue.  Infusible.  Decom- 
posed by  hot  sulphuric  acid.  Lenzinite  and  Glagerite  are  identical  or 
closely  related.  Kollyrite  is  also  very  similar  in  general  characters, 
but  contains  40  per  cent.  H2O,  with  46  APO3,  and  only  14  SiO2. 


MINERAL   TABLES  I — XXV.  221 

(Assume  a  pale-red  colour  after  ignition  with  Co-solution,  or  do  not  become  blue. 
In  the  bulb-tube,  generally  blacken). 

STEATITE  (compact  or  fine-granular  Talc) :  White,  greenish,  &c., 
often  mottled.  More  or  less  soapy-feeling  and  very  sectile.  On 
ignition,  yields  traces  of  water  only.  See  C2,  below. 

SERPENTINE:  MgO  43-48,  SiO2  43-48,  H2O  13-04;  but  part  of 
the  MgO  very  generally  replaced  by  FeO,  and  small  amounts  of 
NiO,  APO3,  and  Cr2Os,  are  occasionally  present.  In  fine-granular  or 
compact  masses,  or  occasionally  slaty  or  fibrous.  Sometimes,  also,  in 
pseudomorphs  after  Olivine,  Pyroxene,  Spinel,  and  other  species. 
Of  various  colours,  but  chiefly  some  shade  of  green,  greenish-  or 
greyish-yellow,  brown,  or  red,  two  or  more  colours  in  irregular 
patches  being  often  present  in  the  same  specimen;  translucent  or 
opaque;  H  3-0-4-0;  sectile;  G  2-5-2-7.  BB,  whitens,  and  fuses  on 
thin  edges.  Deeply-coloured  (ferruginous)  varieties  do  not  redden 
distinctly  with  Co-solution.  Decomposed  by  sulphuric,  and  also, 
though  less  easily,  by  hydrochloric  acid.  Picrolite,  Picrosmine, 
Bowenite,  Tletinalite,  Marmolite,  Antigorite  (see  above,  B1),  Chrysotile 
(see  below),  and  many  so-called  Soapstones,  are  varieties, 

CHRYSOTILE  (Serpentine-Asbestus) :  Properly,  a  fibrous  asbestiform 
serpentine,  in  silky,  easily  separable  fibres,  of  a  yellowish,  greenish- 
white,  or  oil-green  colour.  BB,  a  fine  fibre  melts  at  the  extreme 
point.  Baltimorite  is  a  bluish,  coarsely  fibrous  variety,  often  con- 
taining APO3  and  Cr203.  Metaxite  is  also  a  fibrous  serpentine. 

MEERSCHAUM  (Sepiolite)  :  MgO,  SiO2,  H2O  (the  latter  somewhat 
variable,  but  usually  11  or  12  per  cent.).  In  fine-granular,  more  or 
less  compact  and  very  sectile  masses  of  a  white,  pale-yellow  or 
greyish  colour.  Sometimes  in  pseudomorphs  after  Calcite,  &c.  H 
1-5-2-5;  G  about  1-0-1-3.  BB,  hardens,  and  melts  on  thin  edges. 
Decomposed  by  HC1  acid,  with  separation  of  slimy  silica. 

DEWEYLITE  (Gymnite)  :  MgO  37,  SiO2  41,  H2O  22.  In  more  or 
less  compact  masses  of  a  dingy  yellow  or  yellowish-white  colour  and 
somewhat  waxy  lustre;  H  2-0-3-0;  G  1-9-2-22.  BB,  fuses  only  on 
the  thinnest  edges.  Decomposed,  without  gelatinization,  by  hydro- 
chloric acid.  Kerolite  is  closely  related  in  general  characters  and 
composition. 

YILLARSITE  :  MgO,  FeO,  MnO,  SiO2,  H2O.  In  pyramidal  or  thick 
tabular  crystals  (apparently  rhombic,  and  probably  pseudomorphous 


MRS  BLOWPIPE    PRACTICE. 

after  Olivine),  arranged  generally  in  compound  groups ;  also  in 
rounded  granular  masses;  green,  dingy-yellow,  or  greyish;  H  3'0  ; 
G  2-9-3-0.  Infusible.  Decomposed  by  acids. 

PYRALLOLITE:  MgO,  CaO,  A1203;  SiO2,  H20.  Commonly  in 
prismatic,  coarse-fibrous,  or  granular  masses,  rarely  in  Clino-Rhombic 
crystals  with  basal  cleavage ;  green,  greenish-white,  pale  yellowish- 
grey ;  H  3-0-4-0;  G  2-53-2-73.  Fusible  on  thin  edges  only.  Gener- 
ally regarded  as  an  altered  Pyroxene. 

C2.— YIELD  NO  WATER  (OR  TRACES  ONLY)  BY  IGNITION  IN  BULB-TUBE. 

f  Sectile. 

(  With  Co-solution  assume  a  flesh-red  colour). 

STEATITE  (compact  or  fine-granular  Talc):  MgO  31*7,  SiO2  63-5, 
H2O  4-8 — but  the  latter  is  only  evolved  on  intense  ignition.  Massive : 
fine-granular  or  compact;  also  in  pseudomorphs  after  Scapolite, 
Orthoclase,  Andalusite,  Spinel,  Pyroxene,  and  other  species ;  white, 
grey,  greenish,  reddish,  &c.,  often  mottled;  H  1-5-2-5;  very  sectile  ; 
G  2-6-2-8;  more  or  less  soapy-feeling.  BB,  hardens  considerably, 
and  fuses  on  thin  edges.  Decomposed  by  hot  sulphuric  acid. 

f  f  Not  sectile. 

(Forming  zinc- sublimate  on  charcoal  by  fusion  with  carb.  soda  and  borax). 

WILLEMITE:  ZnX)  73,  SiO2  27..  Hemi-Hex.  (crystals  small,  fre- 
quently with  rounded  edges,  mostly  hexag.  prisms  terminated  by  a 
rhombohedron.  measuring  1^8°  30'  over  a  polar  edge*) ;  white,  green, 
brownish,  reddish,  &c. ;  H  5'5  (scratches  glass  feebly);  G  3'9-4-2. 
BB,  infusible,  or  vitrified  here  and  there  on  surface  only.f  With 
Co-solution  becomes  green,  or  green  and  blue.  Gelatinizes  with 
hydrochloric  acid. 

TROOSTITE  (Manganesian  Willemite) :  Like  Willemite  in  general 
composition,  but  with  part  of  the  ZnO  replaced  by  MnO  and  FeO. 
Commonly  in  opaque  or  semi-opaque  yellowish -grey  or  brown  crystals 
like  those  of  Willemite,  but  comparatively  large.  BB,  with  carb. 
soda,  strong  Mn-reaction.  Gelatinizes  with  HC1  acid. 

*  This  rhombohedron  is  commonly  regarded  as  the  form  f  R.  In  the  form  R,  the  angle  over 
a  polar  edge  equals  116° ;  and  in  the  form  — £  R,  also  often  present  (especially  in  the  manganese 
variety  Troostite),  it  equals  143°  24'. 

t  A  small  splinter  scarcely  becomes  rounded  or  changes  form,  but  if  examined  by  the 
magnifying  glass  after  exposure  to  the  blowpipe,  its  surface  exhibits  points  of  vitrification. 


MINERAL    TABLES: — XXV. 

{Forming  with  borax,  BB,  a  glass  which  becomes  opaque  on  flaming.     Moistened 

with  sulphuric  acid,  tinges  the  flame-point  pale-green}, 
XENOTIME:  YO,  CeO,  P205.     See  under  the  Phosphates,  TABLE 
XVII.,  page  164.     This  rare  species  is  referred  to  here,  as  from  its 
general  insolubility  in  acids  and  its  slow  solution  BB  in  phosphor- 
salt,  it  might  escape  detection  as  a  phosphate. 

(Slowly  attacked,  BB,  by  borax,  the  bead  remaining  clear  when  flamed). 

CHIASTOLITE  :  Properly  a  variety  of  Andalusite,  but  of  lower 
degree  of  hardness  (5'0-5'5)  from  incipient  alteration.  Occurs  in 
slender  straw-like  prisms,  or  occasionally  in  thicker  crystals,  imbedded 
chiefly  in  clay-slate  or  mica-slate,  and  presenting  on  the  transverse 
section  a  dark  cross,  or  a  black  lozenge  at  centre  and  angles.  See 
TABLE  XXIV.,  page  199. 

ANTHOPHYLLITE  :  In  yellowish-brown,  greenish-grey,  or  bronze-- 
green, lamellar  or  fibrous  masses;  H  5-0-5-5;  G  3 '2.  BB,  vitrifies 
on  thinnest  edges  only,  into  a  black  magnetic  enamel.  The  borax- 
ijlass,  coloured  by  iron.  See  under  B2,  above, 

D. — Streak-powder,  black  or  greyish-black. 
This  subdivision  includes  merely  varieties  of  ANTHRACITE  in  which 
the  lustre  is  more  or  less  non-metallic.  When  pure,  Anthracite  con- 
sists essentially  of  carbon,  but  usually  contains  a  small  percentage  of 
H,  N,  and  O,  besides  intermixed  mineral  matter  or  so-called  "ask" 
H  2-5-3-25  ;  G  1-2-1-8.  BB,  in  splinters  practically  unchanged,  but 
in  fine  powder  burns  gradually  away.  In  the  bulb-tube  generally 
yields  a  small  amount  of  water.  Not  attacked  by  the  fluxes.  In- 
soluble in  acids  and  caustic  alcalies-. 


NOTE  ON  TABLE  XXV. 

The  minerals  which  belong  properly  to  this  Table  comprise  a  series  of 
infusible  or  difficultly  fusible  silicates  of  low  or  comparatively  low  degree  of 
hardness,  many  yielding  to  the  finger-nail,  and  all  being  readily  scratched  by 
the  point  of  a  knife.  Whilst  some  of  these  silicates  are  definite  species,  pre- 
senting a  fixed  composition  and  well  defined  physical  characters,  others  are 
mere  mixtures,  or  more  or  less  unstable  products  of  decomposition.  The 
latter  in  many  cases  can  only  be  distinguished  from  one  another  by  complete 
chemical  analysis ;  and,  as  a  rule,  no  two  examples  of  these  pseudo-species, 
unless  obtained  from  absolutely  the  same  spot,  will  be  found  to  agree  exactly 


224  BLOWPIPE    PRACTICE. 

in  the  amount  of  water  or  other  components.  False  species  of  this  unstable 
and  indefinite  character  are  easily  made  by  any  one  capable  of  performing  an 
ordinary  mineral  analysis,  but  their  acceptance  leads  to  much  confusion,  and 
should  therefore  be  rigorously  disallowed.  In  Tables  of  the  present  character, 
however,  products  of  this  kind,  already  recognized  in  mineralogical  systems 
and  text-books,  could  not  be  altogether  ignored.  By  a  little  latitude,  the 
greater  number  might  be  placed  under  two  conventional  species  :  the  first 
including  all  hydrated  magnesian  or  alumino-magnesian  products  of  the  kind 
in  question ;  and  the  second,  all  the  purely  or  essentially  aluminous  matters 
of  this  kind. 

The  more  common  representatives  of  the  Table  belong  to  the  following 
groups : — Micas,  Chlorites,  Talcs  and  Steatites,  Serpentines,  Kaolins,  Pinites, 
Copper  Silicates,  Zinc  Silicates. 

The  micas  are  especially  characterized  by  their  metallic  pearly  or  general 
pseudo-metallic  lustre,  and  their  ready  cleavage  into  thin,  elastic  leaves. 
Those  of  the  present  Table  include  the  three  species,  Muscovite,  Phlogopite, 
and  Biotite — the  two  latter  essentially  magnesian  species.  Muscovite,  com- 
monly called  Potash  Mica,  although  the  other  species  contain  an  equal  or 
even  greater  amount  of  potash,  is  chiefly  distinguished  by  its  want  of  solu- 
bility in  sulphuric  acid,  whilst  the  other  two  species,  when  in  fine  powder, 
are  decomposed  in  the  boiling  acid,  with  separation  of  fine  scales  of  silica. 
Phlogopite  is  generally  of  a  golden-brown  colour  ;  Biotite,  dark-green  or  black. 
The  optical  characters  of  these  micas  are  also  different.  Muscovite  is  biaxial, 
with  angle  of  divergence  44°-78° ;  Phlogopite  is  also  biaxial,  but  with  smaller 
divergent  angle  (under  20°,  sometimes  under  5°) ;  and  Biotite  is  (normally) 
uniaxial.  In  thin  scales,  all  melt  without  difficulty  on  the  edges  into  an 
opaque- white  or  greyish  enamel ;  and  when  moistened,  after  ignition,  with 
hydrochloric  acid,  all  shew  in  the  spectroscope  the  red  K-line,  with  in  some 
cases  the  Li-line  also.  Some  examples  shew  one  or  both  of  these  spectra  by 
simple  insertion  per  se  in  the  flame.  Red  and  green  Ca-lines  sometimes 
appear  from  intermixed  calcite.  Muscovite  is  commonly  present  in  granites, 
gneiss  and  mica  slate,  as  one  of  the  essential  components ;  Phlogopite  is 
chiefly  found  in  the  bands  of  crystalline  limestone  associated  with  many 
gneissoid  rocks ;  and  Biotite  occurs  most  generally,  though  not  exclusively, 
in  lavas,  trachytes,  and  basalts. 

The  Chlorites  are  chiefly  distinguished  by  their  dark-green  colour  and  foli- 
ated structure ;  their  flexibility  in  thin  leaves  (without  the  elasticity  of  the 
micas);  their  softness;  and  the  marked  amount  of  water  (about  12  p.  c. ) 
which  they  yield  by  ignition  in  the  bulb-tube.  Some  chlorites,  however, 
especially  chromiferous  examples,  present  a  deep-red  colour.  In  thin  scales, 
all  fuse  more  or  less  readily  on  the  edges  into  a  greyish  or  black  enamel,  the 
latter  often  magnetic.  The  original  Chlorite  has  been  split  up  into  several 
species,  more  or  less  distinct.  The  principal  comprise  Chlorite  proper  or 
Pennine  (the  Ripidolite  of  Gustav  Rose)  characterized  by  its  hexagonal  or 
rhombohedral  crystallization  ;  and  the  clino-rhombic  species,  Clinochlore  or 
Ripidolite  (of  von  Kobell),  for  which  the  old  name  of  Chlorite  was  retained 


MINERAL    TABLES  : — XXV.  225 

by  Rose.  These  species  closely  resemble  one  another,  and  in  ordinary,  un- 
crystallized  examples  they  can  scarcely  be  distinguished.  As  a  rule,  however, 
Chlorite  is  a  more  ferruginous  species,  and  thus  generally  becomes  magnetic 
after  fusion  or  strong  ignition,  and  its  sp.  gr.  is  in  some  examples  as  high  as 
2-9  ;  whilst  that  of  Ripidolite  rarely  exceeds  2'7.  This  distinction,  however, 
only  applies  in  special  cases,  and  is  practically  of  little  value. 

The  Talcs  and  Steatites  are  exclusively  or  essentially  magnesian  silicates, 
containing  4  or  5  p.  c.  of  apparently  basic  water,  only  expelled  by  intense 
ignition.  Hence,  by 'ordinary  ignition  in  the  bulb-tube,  these  minerals  yield, 
as  a  rule,  merely  traces  of  moisture,  and  they  are  thus  generally  placed  among 
anhydrous  species  in  determinative  groupings.  The  formula  may  be  written 
(H20,  3  MgO),  4  SiO2.  Talc  proper  is  easily  recognized  by  its  occurrence  in 
soft,  flexible,  more  or  less  pearly  scales  and  foliated  masses  of  a  white,  clear- 
green  or  other  light  colour,  combined  with  its  soapy  feel,  and  its  property  of 
assuming  a  flesh-red  tint  by  ignition  with  cobalt-solution,  the  latter  character 
serving  to  distinguish  it  from  pyrophyllite  and  other  foliated  minerals  of  the 
aluminous  Kaolin  group.  Although  very  soft  and  flexible,  the  folise  are 
inelastic.  Steatite  is  a  more  or  less  compact  Talc,  usually  white,  grey, 
greenish,  reddish,  or  mottled  in  colour,  and  very  sectile.  It  usually  gives 
distinct  traces  of  water  on  ignition,  and,  like  ordinary  talc,  it  hardens  greatly 
and  becomes  vitrified  on  thin  edges  in  the  blowpipe  flame.  Sub-slaty  vari- 
eties, forming  a  transition  into  Talc  proper,  occasionally  occur. 

The  Serpentine  group  is  closely  related  to  that  of  the  Talcs  and  Steatites, 
its  included  species  being  essentially  hydrated  magnesian  silicates,  compara- 
tively soft  and  sectile  ;  but  (unlike  the  Talcs)  all  yield  a  distinct  amount  of 
water  on  moderate  ignition.  The  group  is  chiefly  represented  by  Serpentine 
proper  ;  the  asbestiform  variety  or  sub-species  of  the  latter,  known  as  Chry- 
sotile  ;  the  foliated  or  schistose  varieties  or  sub-species,  Antigorite,  Schiller 
Spar,.  &c. ;  and  the  related  magnesian  silicates,  Meerschaum,  Deweylite  or 
Uymnite,  Kerolite,  and  other  similar  compounds.  Most  of  these  are  decom- 
position products  of  more  or  less  unstable  character.  In  the  Serpentines,  the 
amount  of  water  averages  12  per  cent.,  but  in  Deweylite  and  in  many 
Meerschaums  it  exceeds  20  per  cent.,  and  is  still  higher  in  Kerolite.  Serpen- 
tine proper  is  commonly  in  beds  or  masses  of  fine-granular  or  occasionally 
sub- slaty  structure,  and  of  dark-green,  yellow,  brown,  red,  or  other  colour, 
two  or  more  tints  or  shades  of  colour  frequently  occurring  in  the  same  speci- 
men. The  so-called  "Noble  Serpentine "  is  more  or  less  translucent  and  of 
rich  shades  of  colour  ;  whilst  "Common  Serpentine"  is  opaque  or  translucent 
on  the  edges  only,  and  comparatively  dull  or  muddy  in  colour.  Mixtures  of 
serpentine  with  calcite  or  dolomite  are  known  as  Ophiolite,  Verde  Antique,  or 
Serpentine-marble.  Serpentine  is  unknown  in  true  crystals,  but  frequently 
occurs  in  pseudomorphs  (essentially  pseudoinorphs  of  alteration)  derived  from 
Oliviiie,  Pyroxene,  Spinel,  and  other  magnesian  species. 

The  Kaolins  present  a  remarkable  resemblance  in  outward  characters  to 
many  Talcs  and  Steatites,  some  representatives  of  the  group  (Pyrophyllite, 
&c.)  being  made  up  of  soft,  flexible,  pearly,  and  foliated  masses,  whilst  others 
16 


226  BLOWPIPE    PRACTICE. 

are  fine-granular  (or  microscopically  scaly)  in  structure,  and  more  or  less  soapy 
to  the  touch.  But  the  Kaolins  are  essentially  aluminous,  and  thus  assume  a 
distinct  blue  colour  after  ignition  with  cobalt-solution.  The  principal  repre- 
sentatives of  the  group  comprise  Kaolin  proper,  Nacrite  or  Pholerite,  Pyro- 
phyllite,  Agalmatolite,  Halloysite,  and  Kollyrite.  These  are  sufficiently 
described  in  the  Table.  All  are  essentially  decomposition  products. 

The  Finite  group  consists  of  crystallized  pseudomorphous  products  derived 
from  the  alteration  of  lolite,  or  apparently  in  some  cases  from  that  of  Nephe- 
line  or  other  species.  .These  substances  are  chiefly  in  six-sided  or  twelve- 
sided  prisms,  often  more  or  less  ill-formed,  with  dull  lustre,  and  dingy- white, 
pale-grey,  greyish-green,  dull-blue,  reddish,  or  dark-brown  colour.  The  hard- 
ness is  under  4'0  (usually  2 -5-3*5),  and  the  sp.  gr.  about  2 '6  or  2*8.  They 
may  be  grouped  conveniently  under  three  series,  typified  respectively  by 
Finite,  Esmarkite  and  Gigantolite.  The  minerals  referrible  to  Finite  and 
Esmark.ite  are  fusible  on  the  edges  only  ;  those  referred  to  Gigantolite  melt 
before  the  blowpipe  more  or  less  readily.  These  latter,  therefore,  come  under 
notice  in  Table  XXVII.  In  the  Finite  series,  a  certain  amount  of  potash  is 
always  present  (although  that  alkali  has  not  been  found  in  the  supposed 
parent-stock,  lolite),  and  the  included  forms  (Finite,  Weissite,  Fahlunite, 
Pyrargillite,  Iberite,  &c.)  shew  very  distinctly  the  red  K-line  in  the  spectro- 
scope, after  being  ignited  and  then  moistened  with  hydrochloric  acid,  or  by 
fusion  with  carbonate  of  soda  or  fluor-spar.  The  yellow  Na-line,  and  the 
green  and  red  Ca-lines  from  the  fluor-spar,  may  be  entirely  cut  off  by  the 
intervention  of  a  piece  of  deep-blue  glass.  The  representatives  of  the  Esmar- 
kite series,  on  the  other  hand  (including  Esmarkite,  Bonsdorfnte,  Praseolite. 
Aspasiolite,  &c.),  do  not  contain  potash. 

The  group  of  Copper  Silicates  includes  the  rare  Dioptase  and  the  compara- 
tively common  Chrysocolla,  the  latter  including  in  the  Table  both  the  green 
and  blue  varieties.  The  characters  of  these  are  sufficiently  given  in  the  text. 
The  amorphous  Chrysocolla,  as  a  rule,  will  alone  come  under  the  student's 
observation. 

The  Zinc  Silicates,  which  include  the  anhydrous  Willemite,  with  its  man- 
ganese-holding variety,  Troostite,  and  the  hydrous  species  Calamine,  are  also 
described  in  sufficient  detail  in  the  Table.  They  find  a  place  also  in  Table 
XXIV. ,  as  in  most  examples  they  are  sufficiently  hard  to  scratch  glass  slightly. 
They  do  not  readily  yield  a  zinc  sublimate  on  charcoal,  unless  fused  in  powder 
with  a  mixture  of  carb.  soda  and  borax,  or  treated  according  to  the  method 
recommended  at  page  39.  With  cobalt-solution  they  assume  partly  a  green 
and  partly  a  blue  colour,  the  latter,  more  especially,  after  strong  ignition. 


[227] 


TABLE    XXVI. 

[Lustre  non-metallic  (in  some  cases  pseudo-metallic).  Slowly  or  incompletely 
dissolved,  BB,  by  phosphor-salt.  More  or  less  readily  fusible.  Yielding 
no  water  (or  merely  traces)  on  ignition]. 

A. — Fusible  into  a  black  or  very  dark  bead,  magnetic  or 
non-  magnetic.* 

Ai.— OCCURRING  IN  SCALY,  MICACEOUS,  OR  ASBESTIFORM  EXAMPLES. 

f  Scaly  or  micaceous.     Readily  decomposed  by  hydrochloric  acid. 

LEPIDOMELANE  :  K2O  9-20,  FeO  1243,  APO3  11-60,  Fe2O3  27-66, 
SiO2  37*40,  with  traces  of  H2O,  &c.  In  hexagonal  tables  and  scaly 
masses  of  a  black  colour  with  greenish  streak,  the  scales  somewhat 
brittle ;  H  2'5-3'0  ;  G  3-0-3-2.  BB  forms  a  black  magnetic  glass  or 
enamel. 

ASTROPHYLLITE  :  K'O,  Na2O,  CaO,  MgO,  MnO,  FeO,  Fe2O3,  A12O3, 
SiO2,  with  7-66  per  cent.  TiO2  and  a  little  H2O,  according  to  Pisani's 
analysis.  In  six-sided  tables  and  micaceous  prisms  of  a  bronze-yellow 
colour  and  metallic-pearly  lustre.  Folise  slightly  elastic.  BB  easily 
fusible  with  some  bubbling  into  a  black,  more  or  less  magnetic  bead. 
The  HC1  solution,  slightly  diluted  and  boiled  with  a  piece  of  tin, 
assumes  an  amethystine  colour. 

w%  In  the  spectroscope  both  Lepidomelane  and  Astrophyllite,  when  moist- 
tened,  after  ignition,  with  HC1  acid,  shew  the  red  K-line. 

f  f  Readily  decomposed  by  sulphuric  acid.     Structure  micaceous. 

BIOTITE  (Potassic  Ferro-magnesian  Mica) :  Mostly  in  dark-green 
or  black  micaceous  examples,  with  flexible  folise.  Fusible  on  the 
edges  only  :  See  TABLE  XXV. 

f  t  f  Fibrous.     Insoluble  in  acids. 

BYSSOLITE  (Ferruginous,  asbestiform  Amphibole) :  In  fibrous 
masses  of  a  green  or  greenish-brown  colour.  BB,  fuses  into  a  black 
and  often  magnetic  bead. 

A«.  —OCCURRING  IN  CRYSTALLIZED,   LAMELLAR,   GHANULAR,  OR   OTHER  NON- 
MICACEOUS  EXAMPLES. 

f  Easily  decomposed,  with  gelatinization,  by  hydrochloric  acid. 

(Fusion-Jbead  magnetic.) 

FAYALITE  :  FeO  70-6,  SiO2  29-4,  but  part  of  the  Fe  in  some 
examples  replaced  by  Mn  \  intermixed  FeS  or  FeS2  also  frequently 

*  The  silicates  of  this  Division  form  also  in  most  cases  a  black  glass  by  fusion  with  carb. 
soda. 


228  BLOWPIPE  PRACTICE: 

present.  In  black  or  greenish-black  masses,  commonly  magnetic? 
from  intermixed  pyrrhotine  or  magnetite;  H  6 '0-6 -5;  G  4'0-4'2, 
BB,  easily  fusible  into  a  black  magnetic  bead. 

HYALOSIDERITE  (Ferruginous  Chrysolite):  MgO,  FeO,  SiO3.  In 
small  prismatic  crystals  of  the  Rhombic  System,  yellowish-brown  in 
colour;  H  6-0-6-5  ;  G  3-4-3*5 ;  BB,  fusible  only  in  fine  splinters  into 
a  black  more  or  less  magnetic  slag. 

ILVAITE  or  LIEVRITE  :  CaO  13-7,  FeO  35-2,  Fe*O3  19-6,  SiO2  29-3 
(with  2-2  basic  water1?).  Rhombic;  crystals  essentially  prismatic,, 
with  V:V  112°  38',  and  V2  :  V2  106°  15',  the  Y  planes  in  most 
crystals  longitudinally  striated  ;  also  in  coarsely  fibrous,  columnar, 
and  granular  masses ;  black,  brownish-black,  with  dark  streak ;  H 
5-5-6-0;  G  3-8-4-1.  Easily  fusible  into  a  black  magnetic  bead. 
Moistened  with  HC1  acid,  shews  red  and  green  Ca-lines  in  spectro- 
scope very  distinctly. 

ORTHITE  or  ALLANITE  (Cerine):  CaO,  CeO,  LaO,  FeO,  FeW, 
APO3,  SiO2,  with,  in  some  examples,  YO,  MgO,  H2O,  &c.  Clino- 
Rhombic  :  crystals  in  general  transversely  elongated,  but  sometimes 
tabular ;  occurs  also  in  columnar  and  fine  granular  examples,  mostly 
of  a  pitch-black  colour  and  somewhat  sub-metallic  aspect ;  but  also 
brown  or  dull  greyish-yellow,  and  then  more  or  less  resinous  in  lustre ; 
H  5-5-6-0;  G  2-8-3-8  or  4-0.  BB  melts  easily,  with  bubbling,  into 
a  dark,  generally  magnetic,  bead.  Bodenite,  Bagrationite,  Erdmaii- 
nite,  and  Muromontite,  are  probably  varieties. 

ALLOCHROITE  (Ferro-calcareous  Garnet) :  CaO,  FeO,  SiO2.  Chiefly 
in  rhombic  dodecahedrons  of  a  dark -red,  dark -green,  or  brown  colour. 
Easily  fusible.  Decomposed,  with  gelatinization,  by  hydrochloric 
acid  in  some  examples,  only.  See  under  Garnet,  below,  page  230. 

SIDEROMELANE  :  CaO,  Fe203,  A1203,  SiO2,  with  small  amounts  of 
MgO,  MnO,  K2O,  NaO.  In  black  amorphous  masses  resembling 
black  Obsidian;  H  6-0;  G  2-55-2-60.  Easily  fusible  into  a  black 
magnetic  slag.  Practically  identical  with  Tachylite,  but  distinguished 
by  its  larger  amount  of  iron,  and  by  dissolving  somewhat  less  readily 
in  hydrochloric  acid. 

(Fusion-globule  not  magnetic.     No  sulphur-reaction.} 
TACHYLITE  :  CaO,  FeO,  A12O3,  SiO2,  with,  in  general,  small  amounts 
of  K2O  and  Na2O,  MnO,  MgO,  and  sometimes  TiO2.     In  black  or 
brownish-black  amorphous  masses  of  vitreous  lustre,  much  resembling 


MINERAL  TABLES  : — XXVI.  229 

some  Obsidians.  H  6-0-6-5  ;  G  2-51-2-60.  BB,  easily  fusible  with 
bubbling  into  a  black  (non-magnetic)  glass  or  enamel.  In  spec- 
troscope, shews  Ca-lines,  and  in  many  examples  the  red  K-line  also. 
An  essentially  volcanic  or  trappean  product. 

TEPHROITE  :  MnO  70-3,  SiO2  29 -7>  In  granular,  cleavable  masses 
of  a  reddish-grey  or  dull  reddish-brown  colour,  weathering  brownish- 
black  :  the  cleavage  rectangular.  H  5'5-6'0;  G  4-0-4-12.  Easily 
fusible  to  a  black  slag.  With  carb.  soda  gives  strong  manganese- 
reaction.  Knebelite  is  probably  identical,  although  said  to  be  in- 
fusible.* Tephroite  differs  essentially  from  the  more  common  man- 
ganese silicate  Rhodonite,  by  its  ready  gelatinization  in  HC1  acid. 
Rhodonite  being  practically  insoluble. 

{fusion-product  not  magnetic.  Strong  sulphur •-reaction.-]') 
HELYINE  :  BeO,  MnO,  FeO,  SiO2  with  Mn,  Fe,  S.  Reg.;  crystals 
chiefly  tetrahedral ;  occurs  also,  though  rarely,  in  botryoidal  masses ; 
H  5-5-6-5;  G  3-2-3-4;  yellow,  brownish,  yellowish-green.  BB,  in 
O.F.  a  dark  bead,  dull  yellow  in  R.F.  In  hydrochloric  acid,  evolves 
odour  of  sulph,  hydrogen,  and  is1  decomposed  with  gelatinization. 

DANALITE  :  A  flesh-red  or  yellowish-grey  Helvine,  with  MnO 
largely  replaced  by  ZnO.  Crystallizes  in  regular  octahedrons,  some- 
times with  truncated  edges,  and  occurs  also  in  small,  disseminated 
grains.  Blowpipe  and  acid  reactions  like  those  of  Helvine  proper, 
but  a  zinc-sublimate  formed  (with  carb.  soda  and  borax)  on  charcoal 

t  f  Decomposed  imperfectly  by  hydrochloric  acid,  but  completely  by 

sulphuric  acid. 

SPHENE  (Titanite1):  OaO  (partly  replaced  by  FeO  and  MnO)  28'57, 
TiO2  40-82,  SiO2  30'61.  Clino-Rh.;  crystals  mostly  small,  with  more 
or  less  ortho-rhombic  aspect,  often  tabular  and  frequently  twinned  : 
see  Note  at  end  of  Table  ;  brown,  grey,  yellow,  green,  &c. ;  occurs 
also  in  cleavable  and  fine-granular  masses ;  dark-brown,  light-brown, 
grey,  yellow,  green,  &c.;  H  5-0-5-5  ;  G  3'4-3'6  ;  lustre  vitreo-resinous. 
BB,  commonly  becomes  yellow  and  melts  with  bubbling  to  a  dark 
^enamel.  The  sulphuric  acid  solution  (or  the  aqueous  solution  obtained 
by  fusing  the  finely  ground  mineral  with  bisulphate  of  potash) 

*  Judging  from  its  stated  characters  and  composition,  its  infnsibility  is  most  improbable. 
I  have  tried  without  success  to  procure  a  specimen  for  comparison. 

t  See  page  61,  Experiment  1.  The  carb.  soda  should  be  used  somewhat  in  excess.  These 
,:uinerals  give  also  a  strong  Mn-reaction. 


230  BLOWPIPE    PRACTICE. 

assumes  a  violet  colour  if  boiled  with  a  few  drops  of  hydrochloric 
acid  and  a  piece  of  tin*.  In  spectroscope,  shews  red  and  green  Ca-lines 
if  moistened  with  HC1  acid  after  strong  ignition. 

KEILHAUITE  (Yttro-titanite) :  CaO,  YO,  APO3,  Fe203,  TiO2,  SiO2, 
Commonly  in  dark  reddish-brown  twin-crystals  resembling  those  of 
Sphene,  but  often  of  comparatively  large  size  ;  H  6-0-7-0  ;  G  3*5-3 -72.. 
BB,  like  Sphene. 

SCHORLAMITE  (Ferro-titanite) :  CaO  29-38,  Fe2O3  20-11,  TiO2  21-34, 
SiO2  26-09,  with  small  amounts  of  MgO,  FeO^  and  alkalies.  Keg.; 
crystals  rare,  commonly  the  Rhombic  Dodecahedron,  or  that  form 
with  the  trapezohedron  2-2,  hence  much  resembling  garnet  crystals. 
Occurs  mostly  in  small  granular  masses  of  a  pitch-black  colour ;  H 
7-0-7-5 ;  G  3-78-3-86.  BB,  fuses  on  the  edges,  or  entirely,  into  a 
black  slag  or  bead ;  other  reactions  like  those  given  under  Sphene. 

\ 

f  f  f  Partially  or  slightly  attacked  in  normal  condition  by  hydrochloric- 
acid,  but  readily  decomposed  by  that  acid  after  fusion,  f 

(During  fusion,  impart  a  red  colour  to  the  flame.} 

FERRUGINOUS  LEPIDOLITE  :  In  brown,  grey,  or  greyish-red  scaly 
aggregations;  H  2-5;  G  2-9-3-0.  BB,  fusible  with  great  bubbling  into- 
a  dark  magnetic  bead.  See  Lepidolite  proper,  under  B2.,  page  234. 

(During  fusion,  impart  a  green  colour  to  the  point  of  the  flame.) 
AXINITE  :  CaO  20'2,  MnO  2-6,  FeO  2-8,  Fe2O3  6-8,  APO3  16-3; 
B2O3  5-61,  SiO2  43-5,  with  small  amounts  of  MgO,  K2O,  and  basic 
H'2O.  Anorthic  ;  crystals  essentially  flat  or  very  thin  rhornboidal 
prisms,  replaced  only  on  single  edges  and  angles ;  brown,  violet-brown^ 
green,  pearl-grey,  amethystine,  different  tints  often  shewing  in  dif- 
ferent directions;  H  G'5-7'0;  G  3-27-3-33.  BB,  easily  fusible,  with 
green  coloration  of  the  flame-point,  to  a  black  bead,  which  generally 
becomes  green  and  translucent  in  the  inner  flame. 

(No  green  or  red  coloration  of  flame,  during  fusion*    Never  in  fibrous,  acicular,. 
or  prismatic  examples. ) 

GARNET  :  Dark  sub-species  ( Almandine,  Aplome,  Andradite,  Pyrope,. 
Melanite,  Spessartine,  &c.):  Average  composition,  RO  33  to  43,  R?O:v 

*  In  fine  powder,  Sphene  ig  also  sufficiently  decomposed  by  hydrochloric  acid  to  give  this 
characteristic  reaction  when  the  solution  is  boiled  with  a  piece  of  metallic  tin. 

t  The  fused  bead  or  slag  must  be  crushed  under  paper  on  the  anvil,  or  in  a  small  steel  mortar^ 
and  then  ground  to  a  fine  powder* 


MINERAL  TABLES  : XXVI.  231 

21  to  32,  SiO2  35  to  40  (RO  =  CaO,  MgO,  FeO,  MnO  ;  R2O3  -  A120» 
1VOS).  Reg.;  principal  forms,  the  rhombic  dodecahedron  and  the 
trapezohedron  2-2  (see  Note  at  end  of  Table).  Frequently  in  rounded 
grains  and  indistinct  crystals;  red,  brown,  black,  dark-green,  &c. ; 
H  6-5-7-5 ;  G  3-6-4-3  (in  dark  varieties).  *  BB,  fusible  more  or  less 
readily  into  a  dark  and  generally  magnetic  bead.  The  Bohemian 
garnet,  Pyrope,  which  occurs  chiefly  in  small  grains  of  a  deep-red 
colour,  contains  a  small  amount  of  chromium  (CrO  ?),  and  becomes 
black  and  opaque  on  gentle  ignition,  but  recovers  its  red  colour  and 
translucency  on  cooling.  As  shewn  by  Dr.  L.  H.  Fischer,  it  is  only 
decomposed  to  a  slight  extent,  after  fusion,  by  hydrochloric  acid. 

(Essentially  in  fibrous,  acicular,  or  prismatic  examples.) 
EPIDOTE  (Pistacite,  Thallite,  Bucklandite,  Piedmontite,  Withamite, 
«fec.):  CaO  36  to  40,  APO3 18  to  30,  Fe203  7  to  20  or  Mn2O3 10  to  25, 
SiO2  36  to  40,  with  traces  of  MgO,  &c.,  and  about  2  per  cent,  basic 
water.  Clino-Rh. ;  crystals  in  general  elongated  parallel  to  the 
ortho-axis,  with  cleavage  planes  meeting  at  angle  of  115°  24':  see 
Note  at  end  of  Table  ;  occurs  also  in  acicular,  fibrous,  and  other 
examples  ;  green  of  various  shades,  greenish-yellow,  black.  (In  man- 
ganese varieties,  blackish-red  or  dull  cherry-red.)  H  6'0-7'0;  G  3'3-3'5. 
BB,  swells  up,  and  forms  a  dark  cauliflower-like  slag,  or  in  some 
cases  a  black  glass,  generally  magnetic.  In  phosphor-salt,  somewhat 
easily  decomposed,  differing  remarkably  in  this  respect  from  examples 
of  Pyroxene  and  Amphibole  of  similar  aspect. 

t  f  t  f  Very  slightly  attacked  by  hydrochloric  acid,  both  before  and 

after  fusion. 

(In  triangular  or  nine-sided  prisms;  or  in  acicular,  columnar,  or  fibrous  ex- 
amples, triangular  on  cross-fracture. ) 

SCHORL  ;  BLACK  or  DARK-BROWN  TOURMALINE  :  Approximate 
composition  :  MgO  7  or  8,  FeO  5  to  10,  A1203  30,  B2O3  9  or  10, 
SiO2  38,  with  small  amounts  of  K2O,  Na2O,  Li20,  KaO,  MnO,  F,  and 
basic  water.  Henri-Hexagonal  (see  Note  at  end  of  Table) ;  also  very 
commonly  in  columnar  and  fibrous  masses,  the  component  fibres 
shewing  under  the  magnifying  glass  a  triangular  cross  section  ;  Black, 
dark-brown,  with  vitreous  external  lustre  ;  H  7-0-7*5  ;  G  3*03-3-20  ;: 
pyro-electric.  BB,  melts  more  or  less  easily  to  a  black  slag  or  glas.% 
which  often  attracts  the  magnet.  The  fused  bead  reduced  to  fine 
powder  is  decomposed  by  strong  sulphuric  acid,  Alcohol  added  to 


232  BLOWPIPE  PRACTICE. 

the  solution,  and  ignited,  burns  with  the  green  flame  characteristic 
of  B2O3.  The  crushed  bead  made  into  a  paste  with  sulphuric  acid, 
imparts  this  colour  to  the  blowpipe-flame.  A  drop  of  glycerine  in- 
tensifies the  reaction :  see  page  28. 


in  lamellar  or  foliated  masses  with  strongly  pronounced 
one  direction.) 

HYPERSTHENE  (Ferruginous  Bronzite) :  MgO,  FeO,  SiO2.  Rhombic, 
but  crystals  of  quite  exceptional  occurrence  ;  essentially  in  bronze- 
brown,  green,  or  greenish-black,  lamellar  masses,  with  metallic-pearly 
lustre  on  cleavage  plane;  H  5-0-6-0;  G  3-3-3-4.  BB,  fusible  more 
or  less  easily  into  a  black  magnetic  bead  or  slag.  See  under  Bronzite 
in  Table  XXV. 

(In  lamellar  or  fibrous  masses  or  distinct  crystals,  with  cleavage-angle  and  prin- 
cipal prism-angle  near  87°. ) 

AUGITE  (DARK  PYROXENE):  Average  composition,  MgO  12  to  18, 
CaO  18  to  20,  FeO  10  to  13,  APO3  4  to  8,  SiO2  47  to  50,  with  small 

amounts  of  MnO,  &c.     Clino-Rh. ;  the  more  common  crystals  are 

_  / 

eight-sided  prisms,  composed  of  the  forms  V,  Y,  and  V,  with  two 

inclined  summit-planes,  or  large  basal  plane*.    Often  twinned  parallel 

to  V  (see  Note  at  end  of  Table).  Y :  Y  87°  6';  Y  on  Y  90°;  angle 
over  summit-planes  120°  48'.  Commonly,  in  cleavable,  fibrous,  or 
granular  masses.  Black,  greenish-black,  dark-green,  dark-brown ; 
H  5-0-6-0;  G  3-0-3-4.  BB,  fusible  more  or  less  easily  into  a 
black,  generally  magnetic  bead.  Hedenbergite  is  a  non-magnesian 
augite,  consisting  of  CaO  22-18,FeO  29'43,SiO248-39:  black, blackish- 
green,  in  cleavable  masses.  Coccolite  is  a  dark-green  augite,  occuriiig 
in  granular  masses  or  small  crystals  with  rounded  edges  and  angles. 
Breislakite  is  an  acicular  variety  from  Italian  lavas.  Fassaite 
(Pyrgom),  and  some  Sahlites  also  belong  to  the  present  sub-species. 
ACMITE:  WO  13-88,  FeO  6-45,  Fe2O3  28-64J,  SiO2  51-03,  with 
small  amounts  of  K2O,  MnO,  TiO2,  &c.  Clino-Rh.;  crystals  long 
and  thin ;  striated  longitudinally,  and,  as  regards  the  typical  examples, 
imbedded  in  quartz ;  Y  on  Y  87°  15';  H  6-0-6-5  ;  G  3-4-3-53.  Easily 

*  This  plane  is  regarded  by  most  Germaii  crystallographers,  and  by  many  others,  as  a  front  - 
polar  or  hemi-orthodome.  See  the  note  on  the  crystallization  of  Pyroxene  at  the  end  of  the 
present  Table. 

f  Some  mineralogists  make  all  the  iron  Fe203,  but  FeO  is  certainly  present  in  Acmite  as  well. 


MINERAL  TABLES  : — xxvl.  233 

fusible  into  a  black  magnetic  bead.  ^Egirine  is  identical  or  closely 
related. 

JEFFERSONITE  :  CaO,  MgO,  MnO,  ZnO,  FeO,  SiO2,  with  small 
amounts  of  A12O3,  &c."  Clino-Rh.,  but  occurring  only  in  granular 
examples  with  cleavage-angle  of  about  87°  30'.  Dark-green,  brown, 
greenish-black  ;  H  4-5  ;  G  3'3-3'5.  BB,  fusible  into  a  black  bead. 
With  carb.  soda  and  borax  on  charcoal,  gives  a  zinc  sublimate  and 
strong  manganese  reaction.  Hitherto,  only  met  with  at  Sparta,  New 
Jersey.* 

BABINGTONITE  :  CaO  19-32,  MnO  7-91,  FeO  10-26,  Fe2O3  11-00, 
SiO2  51*22,  with  traces  of  MgO,  &c.  Anorthic  (crystals  mostly  short, 
eight-sided  prisms,  with  two  summit-planes).  Occurs  also  in  radiating 
groups.  Black,  greenish -black  ;  H  5-5-6-0  ;  G  3-3-3-4.  Easily  fusible 
into  a  black  magnetic  bead.  Generally  associated  with  Albite  or  Ortho- 
clase.  Distinguished  from  black  augite  only  by  its  crystallization. 

RHODONITE  (Silicate  of  Manganese):  MnO  54-2,  SiO2  45-8,  but 
part  of  the  MnO  commonly  replaced  by  CaO,  FeO,  or  MgO.  Anor- 
thic, but  crystals  of  exceedingly  rare  occurrence  ;  commonly  in  cleav- 
able  masses,  with  cleavage-angle  of  87°  38';  rose-red,  greyish-red, 
weathering  dark-brown;  H  5'0-5'5;  G  3-5-3'65.  BB,  fusible  into 
a  dark-red  or  amethystine  glass  which  becomes  black  and  opaque  in 
the  outer  flame.  With  carb,  soda,  strong  Mn  reaction.  Bustamite, 
in  radiated-fibrous  examples  of  pink  or  pale  greenish-grey  colour,  is  a 
calcareous  variety ;  Fowlerite,  in  coarse  crystals  and  cleavable  masses 
of  a  reddish-brown  or  dull-red  colour,  has  the  MnO  largely  replaced 
by  FeO,  CaO,  and  ZnO. 

(In  lamellar  or  fibrous  masses  or  in  distinct  crystals  with  cleavaye- angle  and 

principal  prism-angle  near  124°). 

HORNBLENDE  ;  DARK  OR  STRONGLY-COLOURED  AMPHIBOLE  (In- 
cludes Common  Hornblende,  Basaltic  Hornblende,  Pargasite,  and 
most  examples  of  Actynolite) :  Average  composition,  CaO  9  to  12, 
MgO  10  to  20,  FeO  8  to  20,  Fe203  5  to  6,  A1203  5  to  15,  SiO2  40  to 
44 ;  but  in  non-aluminous  or  slightly  aluminous  varieties,  the  SiO2 
generally  exceeds  50  per  cent.  Small  amounts  of  Na2O,  K2O,  and 
Fluorine  are  also  usually  present.  Clino-Rhombic ;  crystals  mostly 

,' 

six-sided  prisms,  composed  of  the  forms  Y  and  Y,  terminated  generally 


*  As  the  composition  of  Jeffersouite  does  not  appear  to  be  at  all  constant,  the  mineral  may 
perhaps  be  nothing  more  than  a  mixture  of  Pyroxene  and  Franklinite. 


234  BLOWPIPE    PRACTICE. 

by  three  comparatively  flat  rhombiform  faces  (  =  B  and  P),  also  some- 
times consisting  of  the  prism  V  alone,  terminated  by  two  triangular 
/  / 

planes  P.     The  front  prism-angle  V  on  V  equals  124°  30':  V  on  V 

=  117°  45';  P  on  P=148P  30';  P  on  B=  145°  35';  P  on  P  (over 
summit)  =  148°  16'.  Occurs  also  very  abundantly  in  lamellar, 
fibrous  and  granular  masses ;  colour,  dark-green,  black,  dark-brown  ; 
H  5-0-8-0  ;  G  3-0-3-4.  BB,  fusible  more  or  less  easily  into  a  blffck, 
usually  magnetic  bead.  Cummingtonite  is  a  brown,  fibrous  variety, 
containing  very  little  lime.  Arvedsonite  is  a  closely-related  species 
or  variety  containing  10-60  per  cent.  Na2O.  Mostly  in  black  cleav- 
able  masses,  with  greenish  streak  ;  H  6-0  :  G  3-33-3-60.  Very  easily 
fusible,  with  much  bubbling,  into  a  black,  magnetic  bead*.  See  also 
Glaucophane,  under  B3,  below. 

(In  amorphous,  obsidian-like  masses.) 

WICHTISITE  (Wichtyne) :  Xa'O,  CaO,  MgO,  FeO,  Fe203,  A12O3, 
SiO2.  In  black,  more  or  less  dull,  amorphous  masses,  with  well- 
marked  conchoidal  fracture;  H  6-0-6-5;  G  3-0-3-1.  Fusible,  with 
bubbling,  into  a  black  opaque  bead. 

(In  deep-red  grains  and  rounded  crystals.) 
PYROPE  (Bohemian  Garnet) :  See  under  Garnet,  above. 

(In  flat  tabular  crystals  or  granular  masses.     Sp.  (jr.  over  3*5.) 
CERINE  :  Black,  brownish-black ;  scarcely  attacked  by  hydrochloric 
acid.     See  under  Orthite,  above,  page  228. 

B. — Fusible  into  a  colourless  or  lightly-tinted  bead  or  glass. 

BI.— IMPART  A  DISTINCT  RED  OR  GREEN  COLOUR  TO  THE  BLOWPIPE-FLAME. 

f  BB,  flame  coloured  red. 

(Soft  ;  scaly  or  foliated. ) 

LEPIDOLITE  (Lithionite,  Lithia  Mica):  K2O  4  to  11,  Na2O  1  to  3, 
Li2O  1-5-5;  MnO  2  to  5,  APO3  14  to  .29,  Fe?O3  0  to  28,  SiO'2  40  to 
52,  with  from  4  to  8  per  cent.  Fluorine.  Essentially  in  scaly  aggre- 
gations or  micaceous  masses  of  a  rose-red,  pale-red,  pearl-grey,  or 
greyish-white  colour;  H  2-0-4-0  (commonly  2-5);  G  2-8-3-0.  BB, 
very  easily  fusible  with  great  bubbling  into  a  colourless  blebby  gla^s 


*  Very  thin  splinters  fuse  without  the  aid  of  the  blowpipe,  as  Grst  pointed  out  by  Dr.  L.  H. 
Fischer  :  Clavis  der  Silicate,  p.  11. 


MINERAL  TABLES  : XXVI.  235 

(or,  as  regards  ferruginous  examples,  into  a  dark  metallic  bead),  with 
crimson  coloration  of  the  flame.  In  the  spectroscope,  the  red  Li-line 
and  yellow  Na-line  come  out  very  prominently,  the  red  K-line  sub- 
ordinately*.  After  fusion,  completely  decomposed  by  hydrochloric 
acid. 

CRYOPHYLLITE  :  K20,  Li20,  MgO,  MnO,  FeO,  Fe203,  APO3,  SiO2 
(53-46)  with  2  to  3  Fluorine.  Essentially  in  dark-green,  six-sided, 
micaceous  prisms  and  scaly  masses;  G  2 -9.  BB,  colours  the  flame 
red,  and  fuses  with  great  bubbling. 

(Hard.     Not  micaceous  in  structure. )  • 

PETALITE  :  Li2O  (with  small  amount  of  Na20)  4-42,  A1203  17-80, 
SiO*  77-96.  Essentially  in  lamellar  masses  (Clino-Rh.)  with  cleavage- 
angles  of  117°,  141°  23'  and  101°  30',  but  the  two  latter  often  indis- 
tinct ;  colour,  pale-red,  reddish- white,  or  nearly  colourless ;  H  6 '0-6 -5  ; 
G  2 -4-2 -6.  BB,  colours  flame  pale-red,  and  melts  to  a  colourless 
glass.  In  the  spectroscope,  especially  if  the  test-matter  be  moistened 
with  hydrochloric  acid,  the  red  Li-line  comes  out  very  distinctly. 
Insoluble  in  acids.  Kastor  is  a  variety  in  coarse  Clino-rhombic 
crystals  from  Elba  :  "V  on  V  86°  20'. 

SPODUMENE  (Triphane):  Li2O  6-73,  APO3  29-21,  SiO2  64-06;  but 
part  of  the  LPO  commonly  replaced  by  small  amounts  of  Na2O  and 
K2O  and.  traces  of  CaO.  Clino-Rhombic,  with  V  :-V  87°,  but  crystals 
comparatively  rare.  Commonly  in  cleavable  masses  with  cleavage- 
angles  of  87?  =  V  :  V,  and  133°  30'  =  Y  :  V.  Pale-green,  greenish- 
white,  or  greenish-grey;  H  6-0-7-0;  G  3-12-3-20.  BB,  colours 
flame  distinctly  red,  and  melts  easily,  with  much  expansion  and 
bubbling,  into  a  colourless  glass.  Insoluble  in  acids.  In  spectroscope, 
shews  red  Li-line  and  yellow  Na-line  distinctly. 

f  f  Flame  coloured  green. 

( Very  easily  fusible. ) 

AXINITE  :  Essentially  in  groups  of  thin  sharp-edged  crystals,  brown, 
green,  brownish  violet,  pearl-grey,  or  amethystine  in  colour.  BB, 
melts  in  the  outer  flame  into  a  black  glass,  and  with  carb.  soda  gives 
manganese  reaction.  See  above,  page  230. 

*  The  K-line  is  scarcely  visible  unless  the  Na  and  Li  lines  be  cut  off  by  the  intervention  of  \ 
piece  of  deep-blue  glass* 


236  BLOWPIPE    PRACTICE. 

DANBURITE  :  CaO  22-75,  B2O8  28-45,  SiO2  48-80.  Anorthic  ;  but 
mostly  in  lamellar  massess  with  cleavage-angles  of  110°,  126°  and  93°, 
the  two  latter  more  or  less  indistinct.  Yellowish-white,  pale-yellow  ; 
H  7-0 ;  G  2-95-2-96.  BB,  easily  fusible,  with  green  coloration  of 
the  flame.  The  powder  moistened  after  ignition  with  hydrochloric- 
acid,  shews  in  the  spectroscope  green  B-lines  with  transitory  flashes 
of  the  red  Ca-line. 

(Fusible  with  difficulty  or  on  the  edges  only. ) 

HYALOPHANE  (Barytic  Feldspar) :  K20  7-82,  Na2O  2-14,  BaO  15-05, 
A12O3  21-12,  SiO2  52-67,  with  traces  of  CaO,  MgO,  &c.,  but  the  com- 
position, more  especially  as  regards  the  amount  of  baryta,  appears  to 
be  somewhat  variable.  Clino-Rhombic ;  crystals  practically  identical 
with  those  of  Orthoclase  ;  cleavage  very  perfect  parallel  with  basal 
plane;  white,  pale-reddish;  H  6-0-6-5;  G  2-80.  BB,  fusible  on 
edges  only,  unless  in  thin  splinters.  Distinguished  from  the  feldspars, 
generally,  by  the  green  colour  imparted  to  the  point  of  the  flame.  In 
acids  scarcely  attacked. 

B2.— YIELD  STRONG  REACTION  OF  SULPHUR  OR  CHLORINE.* 

t  Give  sulphur  reaction,  BB,  with  carb.  soda. 

HELVINE  ;  DANALITE  :  Essentially  in  small  tetrahedrons  or  octahe- 
drons, or  in  small  grains,  of  a  yellow,  brownish,  yellowish-green,  or 
reddish-grey  colour.  H  5'5-6-5 ;  G  3'2-3'4.  Gelatinize  and  evolve 
odour  of  sulph.  hydrogen  in  hydrochloric  acid.  BB,  in*  outer  flame 
giv^e  a  black  or  dark  fusion-product.  See  under  A2,  page  229. 

HAUYNE:  K2O  4-96,  Na2O  11-79,  CaO  10-60,  A12O3  27-64,  SiO2 
34-06,  SO3  11-25.  Reg.;  chief  crystal  form,  the  rhombic  dodecahe- 
dron ;  occurs  also  in  small  grains.  Essentially  blue  or  bluish-green, 
rarely  colourless  (Berzeline);  H  5-0-5-5;  G  2'4-2-5.  BB,  decrepitates, 
and  melts  slowly  into  a  pale-blue  or  colourless  glass.  Gelatinizes  in 
hydrochloric  acid. 

NOSINE  (Nosean):  NaO,  A1203,  SiO2,  SO3.  Closely  resembles 
Hauyne  in  crystallization,  and  in  its  blowpipe  and  acid  reactions, 
but  commonly  ash-grey,  greyish-blue,  or  greenish-white  in  colour, 
and  with  larger  percentage  of  soda  (24-89). 

*  See  page  61,  Experiments  1  and  3.  In  testing  for  sulphur,  the  reagent,  carb.  soda,  should 
be  used  somewhat  in  excess. 


MINERAL  TABLES  : XXVI.  237 

LAPIS-LAZULI  :  NaO,  CaO,  SiO2,  SO3,  &c.  Essentially  in  granular 
masses  of  a  rich  blue  colour,  frequently  intermixed  with  calciter 
grains  of  iron  pyrites,  and  other  substances.  When  crystallized,  in 
rhombic  dodecahedrons.  H  5*5  ;  G  2-38-2-45 ;  BB,  melts  easily  to 
a  colourless  glass.  Gelatinizes  in  hydrochloric  acid,  most  examples 
evolving  sulph.  hydrogen  during  decomposition. 

MICROSOMMITE  :  Gives  feeble  S-reaction,  but  strong  reaction  of 
chlorine  :  see  below. 

1 1  Give  Cl-reaction  with  cupreous  phosphor-salt  bead. 

SODALITE  :  Na2O,  A12O3,  SiO2,  NaCl.  Reg. ;  chiefly  crystallized 
in  rhombic  dodecahedrons,  or  in  combinations  of  that  form  and  the 
cube ;  occurs  also  in  granular  examples ;  mostly  colourless  or  green- 
ish-white, less  commonly  blue  or  bluish-green.  H  5-5  ;  G  2-13-2-30, 
BB,  a  colourless  glass.  In  hydrochloric  acid,  gelatinizes. 

MICROSOMMITE  :  K2O,  Na2O,  CaO,  A12O3,  SiO2,  NaCl,  with  small 
percentage  of  SO3  in  most  examples.  Hexagonal ;  chiefly  in  minute 
six-sided  prisms  on  certain  Yesuvian  lavas;  H  6'0;  G  2-6.  BB, 
according  to  Sacchi,  difficulty  fusible.  Gelatinizes  in  hydrochloric 
acid.  The  spectroscope  should  shew  Na,  K,  and  Ca  lines,  but  the 
writer  has  not  been  able  to  procure  a  specimen  for  examination. 

EUDIALYTE  :  Na2O,  CaO,  FeO,  ZrO2,  SiO2,  with  small  amounts  of 
CaO,  MnO,  &c.,  and  about  2  per  cent.  NaCl.  Hemi-Hexagonal;  crys- 
tals, acute  rhombohedrons  with  extended  basal  plane;  R  :  R  73°  30', 
B:R  112°  18'  and  67°  42'.  Dark  purplish-red,  brownish-red. 
H  5-0-5-5;  G  2-8-3-0.  Melts  easily  to  a  greyish-green  glass  or 
Hiiamel.  Gelatinizes  in  hydrochloric  acid.  Eucolite  from  Norway 
is  closely  related.  Both  are  rare  species. 

R*.-NO  DISTINCT  (RED  OR  GREEN)  FLAME-COLORATION.    NO  REACTION  OF 
SULPHUR  OR   CHLORINE. 

f  Decomposed  with  gelatinization  by  hydrochloric  acid. 

(BB,  with  carb.  soda  on  charcoal,  a  distinct  sublimate). 
EULYTINE  (Bismuth  Blende):  Bi2O3  83-75,  SiO2  16-25,  but  gen- 
erally intermixed  with  Fe2O3,  Mn2Os,  P2O5,  Fl,  &c.  Reg. :  crystals 
essentially  tetrahedral,  very  small,  in  drusy  aggregations;  occurs 
also  in  botryoidal  masses;  H  4-5-5-0;  G  about  6*1.  Fusible  into  a 
dull  brownish  bead.  With  carb.  soda  forms  on  charcoal  a  deep- 
yellow  sublimate.  Gelatinizes  in  hydrochloric  acid. 


238  BLOWPIPE    PRACTICE. 

WILLEMITE  :  ZnO,  SiO2.  White,  brownish,  &c.  Fuses  on  edges 
or  surface  only.  With  carb.  soda  and  borax  on  charcoal  gives  a 
zinc-sublimate.  With  Co-solution,  coloured  blue  or  bluish-green. 
See  TABLE  XXV. 

(BB,  with  carb.  soda  no  sublimate.     Colour,  black). 

GADOLINITE  :  Essentially  in  small,  vitreo-resinous  masses  of  a 
black  colour  and  greenish-grey  streak.  BB,  generally  swells  up, 
but  vitrifies  on  edges  only.  See  TABLE  XXIV. 

TSCHEWKINITE  :  CaO,  MnO,  FeO,  CeO,  LnO,  DO,  TiO2,  SiO2, 
with  traces  of  K2O,  Na2O,  &c.  In  more  or  less  compact  masses ; 
velvet-black,  with  brownish  streak;  H  5*0-5-5 ;  G  4-5-4-8.  BB, 
swells  up  into  a  porous  mass,  and  then  melts  slowly  into  a  dull  yel- 
lowish enamel.  Gelatinizes  in  hydrochloric  acid.  The  diluted  solu- 
tion boiled  with  a  piece  of  metallic  tin  assumes  a  violet  colour.  A 
very  rare  species. 

(Colourless  or  lightly -tinted  species.     Fusible  on  thin  edges,  only). 

GEHLENITE  :  Essentially  in  greenish-grey,  or  pale-brownish,  square 
prisms  of  small  size.  Ca-lines  in  spectroscope  readily  brought  out 
by  moistening  the  ignited  test-substance  with  hydrochloric  acid.  See 
TABLE  XXIV. 

MONTICELLITE  (Batrachite)  :    Essentially  in  small  crystals  of  the 

Rhombic  System.  V:V  98°  8',  VJ  :  VJ  133°,  P  :  P  over  summit 
82°  nearly,  P:P  over  front  edge  141°  50';  over  side  edge  82°. 
Colourless,  pale-green,  pale-brownish.  Other  characters  as  in  Geli- 
lenite.  See  TABLE  XXIV. 

(In  platinum  forceps,  more  or  less  readily  fusible.    In  spectroscope,  after  ignition 
and  moistening  with  hydrochloric  acid,  shew  distinct  red  and  green  Ca-lines). 

WOLLASTONITE  (Table  Spar):  CaO  48*28,  SiO2  5172.  Clino- 
Rhombic,  but  crystals  comparatively  rare;  commonly  in  lamellar 
and  fibrous  masses,  with  cleavage  angles  of  95°  30'  and  84°  30'  (  =  B 
on  V) ;  colourless,  pale-reddish  or  yellowish-white,  &c. ;  H  4-5-5*0; 
G  2*75-2*92 ;  in  the  forceps,  thin  splinters  fuse  more  or  less  readily. 
Decomposed,  with  gelatinization  by  hydrochloric  acid. 

HUMBOLDTILITE  (Melilite) :  Na2O,  CaO  (31  or  32),  MgO,  Fe2O3, 
A12O3,  SiO2.  Tetrag.;  crystals  mostly  tabular,  with  large  basal 
plane.;  occurs  also  in  fibrous  and  columnar  examples;  yellowish- 
white,  pale-yellow,  brownish,  <fec. ;  H  5*0-5*5;  G  2*9-2-95.  BB, 


MINERAL  TABLES  : — XXVI.  239 

fusible  with  slight  bubbling  into  a  colourless  or  yellowish  glass. 
Gelatinizes  in  hydrochloric  acid. 

SARCOLITE  :  K2O  1-20,  Na2O  3-30,  CaO  32-36,  Al'O3  21-54,  SiO2 
40*51  (Rommelsberg).  Tetrag. ;  crystals,  mostly  small  square  prisms 
with  replaced  angles  ( =  V,  B,  P) ;  also  sometimes  with  hemihedral 
polar  planes;  pale-red,  reddish-white;  H  5.5-6-0;  G  2-55-2-95 ; 
fusible  into  a  white  blebby  glass  or  enamel.  In  hydrochloric  acid, 
gelatinizes. 

DAVYNE  ;  CANCRINITE  :    See  under  Nepheline,  below. 

(No  Ca-lines  brought  out  in  spectroscope  by  moistening  with  hydrochloric 

acid*). 

NEPHELINE  (Elreolite) :  K2O  4-5  to  6-5,  Na2O  15.5  to  17,  APO: 
34-5  to  35-5,  SiO2  41  to  45.  Hexag.;  crystals  mostly  small  hexa- 
gonal prisms  with  replaced  basal  edges ;  occurs  also  in  lamellar 
masses;  colourless,  white,  pale-brownish,  with. vitreous  lustre  (Ne- 
pheline proper) ;  and  greyish-blue,  bluish-green,  or  red,  with  vitreo- 
resinous  lustre  (Elteolite) ;  H  5-5-6-0;  G  2-55-2-65.  Fusible,  with 
more  or  less  bubbling,  into  a  blebby  glass.  Gelatinizes  in  hydro- 
chloric acid.  Most  examples  shew  the  red  K-line  distinctly  in  the 
spectroscope  if  moistened  with  HC1  acid  after  fusion  or  ignition. 
Davyne  and  Cancrinite  are  partly  altered  varieties,  containing  inter- 
mixed CaO,  CO2,  and  a  small  percentage  of  H2O. 

1 1  Decomposed  by  hydrochloric  acid,  but  without  gelatinization.  f 

( The  hydrochloric  acid  solution  boiled  with  tin  assumes  a  blue  or 
violet  colour). 

SPHENE  (Titanite) :  CaO,  TiO2,  SiO2.  In  Clino-Rhombic  crystals 
and  cleavable  masses  of  a  brown,  yellow,  yellowish -grey  or  green 
colour;  H  5-0-5-5;  G  3-4-3-6.  BB,  melts  generally  into  a  black  or 
dark  enamel,  but  in  some  cases  the  fusion  product  is  dull-yellow. 
See  under  B1,  above,  page  229. 

GUARINITE  :  CaO,  TiO2,  SiO3.  Rhombic,  but  hitherto  only  recog- 
nized in  apparently  square  tables.  Sulphur-yellow.  Fusible  into  a 
yellow  glass. 


*  Unless  intermixed  calcite  be  present,  as  in  many  examples  of  the  Davyne  and  Cancrinitr 
varieties. 

f  In  some  cases,  the  decomposition,  although  sufficiently  marked,  is  more  or  less  in^orri- 
plete.  If  decomposition  ensue  at  all,  the  supernatant  liquid,  diluted  slightly  and  filtered  from 
the  undissolved  residuum,  will  yield  a  distinct  precipitate  with  ammonia,  or  witli  oxalate  (.f 
ammonia>dded  subsequently. 


-40  BLOWPIPE    PRACTICE. 

WOHLERITE  :  Na2O,  CaO,  FeO,  ZrO2,  Nb205,  SiO2.  Rhombic  or 
Clino-Rhombic,  but  crystals  mostly  indistinct ;  commonly  in  small 
angular  grains,  or  in  sub-columnar  masses  and  indistinct  tabular 
forms.  Yellow  of  various  shades,  yellowish-brown;  H  5-0-6-0; 
G  3-41.  BB  melts  easily  into  a  yellowish  bead.  Hitherto  only 
found  in  the  Zircon-syenite  of  Norway. 

(Giving  BB  with  fused  phosphor-salt  in  open  glass  tube  a  strong 
Fluorine-reaction) , 

LEUCOPHANE:  CaO,  BeO,  SiO2,  NaF.  Essentially  in  cleavable 
lamellar  masses  of  a  pale  yellow  or  greenish-grey  colour.  H  3 -5-4-0; 
G  2*9-3.  Strongly  phosphorescent,  and  very  easily  fusible.  Slowly 
decomposed  by  hydrochloric  acid.  See  under  the  Fluorides,  in  Table 
XX,  page  178.  A  rare  species. 

MELINOPHANE  (Meliphanite) :  CaO,  BeO,  SiO2,  NaF.  Occasion- 
ally in  Tetragonal  crystals,  but  commonly  in  lamellar  masses  and 
disseminated  grains  of  a  yellow  colour  ;  H  5*0  ;  G  3.02.  BB,  easily 
fusible  (but  is  said  not  to  phosphoresce?).  Very  rare,  and  still  im- 
perfectly known. 

(Fusible  on  charcoal  into  a  glassy  bead). 

PREHNITE*:  CaO  27-14,  A12O3  24-87,  SiO"  43-63,  H2O  4-36. 
Rhombic ;  crystals  tabular  or  short  prismatic,  generally  aggregated 
in  groups ;  occurs  also  abundantly  in  fibrous- botryoidal  masses,  and 
sometimes  in  pseudomorphs  after  calcite,  analcfme,  &c. ;  H  G-0-7'0  ; 
G  2-8-3-0;  generally  greenish-white,  also  colourless  and  light-green. 
Fuses  very  easily  and  with  much  bubbling.  In  the  bulb-tube,  gives 
off  a  small  amount  of  water,  but  only  at  a  comparatively  high  tem- 
perature. After  fusion  or  strong  ignition,  decomposed  with  gelatin- 
ization  by  hydrochloric  acid,  and  then  shews  in  spectroscope  momen- 
tary red  and  green  Ca-lines. 

WERNERITE  (^Scapolite,  Paranthine,  Meionite,  &c.)  :  Contains  CaO, 
APOa,  SiO2,  in  somewhat  variable  proportions,  with  small  amounts 
of  K2O,  Na2O,  and  IPO.  Tetragonal;  crystals,  commonly,  eight- 
sided  prisms  composed  of  the  two  square  prisms  V  and  V,  with  ter- 
minal polar  planeSj  P,  P,  &c.  (See  note  at  end  of  Table).  P  :  P 
over  middle  edge  63°  42',  over  polar  edge  136°  11' ;  cleavage  parallel 
with  V,  less  distinct  parallel  with  Y;  crystals  often  large,  and  fre- 

*  Belongs  properly  to  Table  XXVII. ,  but  is  referred  to  also  here,  as  the  small  amount  of 
water  which  it  contains  might  in  certain  cases  escape  detection. 


MINERAL  TABLES  : XXVI.  241 

quently  more  or  less  weathered ;  occurs  also  in  columnar,  sub-fibrous, 
granular,  and  other  masses ;  colourless,  white,  greenish-white,  green, 
pale-reddish,  greyish,  &c.;  H  5'0-6'Oj  G  2-6-2-8.  BB,  easily  fusible 
with  more  or  less  bubbling.  In  the  spectroscope,  after  ignition  and 
moistening  with  hydrochloric  acid,  shews  red  and  green  Ca-lines,  in 
most  cases,  very  distinctly.  Meionite  (often  classed  as  a  distinct 
species)  and  Mizzonite  are  varieties  from  Monte  Sornma.  Nuttalite, 
Dipyre,  Couseranite,  Passauite,  are  varieties  from  other  localities. 
Wilsonite,  in  pale  •  purplish-red,  cleavable  and  sub-fibrous  masses,  is 
probably  an  altered  Wernerite  containing  intermixed  CaOCO2. 

GROSSULAR,  and  most  other  light-coloured  GARNETS  :*  CaO,  Ala03, 
SiO2,  &c.  In  crystals  of  the  Regular  System,  chiefly  the  rhombic 
dodecahedron  or  the  trapezohedron  2-2,  and  in  small  rounded  grains  ;: 
H  6-5-7-5;  G  3-15-3-8  (in  grossular,  proper,  usually  about  3*4  or 
3-5);  light-green,  (grossular  prope^),  red,  yellow,  brown,  etc.,  rarely 
colourless.  BB,  more  or  less  readily  fusible  into  a  lightb 
uncoloured  glass. 

(Fusible  in  the  forceps,  but  not  fusible  into  a  bead  on 
ANORTHITE  (Lime-Feldspar  in  part,  Indianite,  Christianize).: 
2010,  A1203  36-82,   SiO2  43-08.     Anorthic;    crystals  often  largo, 

/ 

with  B  and  V  planes  predominating ;  frequently  twinned  parallel  to- 
one  or  the  other  of  these  forms,  to  which  the  cleavage  planes  are 
also  parallel;  cleavage-angles,  85°  50'  and  94°  10';  Right  V  on 
Left  V  120°  30'.  Occurs  also  in  lamellar  and  granular  masses; 
H  6-0;  G  2-66-2-80;  colourless,  white,  pale-reddish,  with  pearly 
lustre  on  cleavage  planes  and  vitreous  lustre  on  other  planes.  BB, 
fusible  into  a  clear  glass.  Completely  decomposed  by  hydrochloric 
acid,  but  without  gelatinization.  In  the  spectroscope,  the  Ca-lines 
come  out  distinctly  after  ignition  and  moistening  with  acid. 

LABRADORITE  (Lime  Feldspar,  Lime-soda  Feldspar,  Labrador  Feld- 
spar) :  NaO,  CaO,  APO3,  SiO2.  Anorthic ;  but  commonly  in  cleav- 
able  masses,  with  cleavage-angles  of  86°  40'  and  93°  20' ;  mostly  light 
or  dark  grey,  with  play  of  green,  blue,  violet,  red,  or  orange,  in 
certain  directions,  but  sometimes  white,  and  without  or  with  very 

*  The  deep-red  and  most  dark  garnets  fuse  into  a  black  and  generally  magnetic  bead,  and 
are  thus  placed  in  section  A  of  the  present  Table.  Many  light  garnets,  again,  are  partially 
decomposed  by  hydrochloric  acid,  whilst  others  are  scarcely  attacked  by  that  reagent.  These 
latter  are  referred  to,  consequently,  under  the  next  sub-section  1 1 1- 

17 


242  BLOWPIPE    PRACTICE. 

feeble  play  of  colour.  H  6'0;  G  2-6-2-8.  Fusible  into  a  clear  glass. 
Slowly  and  only  partially  decomposed  by  hydrochloric  acid.  Spec- 
troscope reaction  as  in  Anorthite. 

f  f  f  Scarcely  attacked  by  hydrochloric  acid. 

(Micaceous  species :  flexible  in  thin  leaves.     Fusible  on  edges  or  in  ihvn 
scales,  only*.) 

MUSCOVITE  (Potash  Mica)  ;  PHLOGOPITE  (Potassic  Magnesian 
Mica ) :  In  thin  leaves,  flexible  and  elastic ;  lustre  more  or  les 
metallic-pearly.  Phlogopite  is  decomposed  by  sulphuric  acid ;  Mus- 
covite, not.  Both  fuse  in  general  on  the  edges  into  a  grey  enamel. 
Biotite  is  also  decomposed  by  sulphuric  acid,  but  melts  on  the 
edges,  as  a  rule,  into  a  black  ferruginous  glass  or  slag.  See  TABLE 
XXV.,  A1. 

TALC  :  MgO,  SiO2.  White,  greenish,  &c. ;  very  soft.  Flexible 
in  thin  pieces,  but  not  elastic;  H'1'0.  More  or  less  soapy  to  the 
touch.  Reddens  by  ignition  with  Co-solution.  See  TABLE  XXV.,  A2. 

(Foliated  species,  with  marked  cleavage  in  one  direction,  but  not  flexible  in 
thin 


MARGARITE  (Pearl  Mica)  :  White,  reddish,  greenish,  &c.,  with 
pearly  lustre ;  H  3'5-4'0.  Fusible  on  the  edges,  often  with  more  or 
less  intumescence,  into  a  greyish  enamel.  See  TABLE  XXV. 

DIALLAGE  :  MgO,  CaO,  SiO2,  with,  commonly,  small  amounts  of 
FeO,  MnO,  APO3,  and  H2O.  In  foliated  or  sub-foliated  masses  or 
indistinct  tabular  crystals  of  a  greyish-green  or  greenish-brovra 
colour  and  metallic-pearly  lustre;  H  about  4-0;  G  3'2-3*4.  Fusible 
more  or  less  easily  into  a  greyish  enamel.  An  aberrant,  schistose 
variety  of  Pyroxene. 

( Very  sectile :  readily  cut  by  the  knife.  Fusible  on  edges  only). 
STEATITE  (Soapstone  in  part) :  MgO,  SiO2.  In  white,  grey,  green- 
ish, reddish,  or  mottled  masses  of  more  or  less  compact  structure,  or 
occasionally  sub-slaty.  Sometimes,  also,  in  pseudomorphs  after  Scapo- 
lite,  Spinel)  and  other  species  ;  H  1-5-2-5.  BB,  hardens  greatly,  but 
only  fuses  on  thin  edges.  Reddens  by  ignition  with  Co-solution. 
Generally  gives  off  traces  of  water  in  the  bulb-tube.  Decomposed 
by  sulphuric  acid.  A  compact  or  non- foliated  variety  of  Talc.  See 
TABLE  XXV.,  C>. 

*  Most  of  these  species,  when  ignited  in  the  bulb-tube,  give  off  traces  of  water. 


MINERAL  TABLES  : — XXVI.  243 

(Asbestiform :  in  soft,  fibrous  masses). 

ASBESTUS  (Amianthus)  :  Essential  components,  CaO,  MgO,  SiO8. 
In  white,  grey,  brownish,  greenish-white,  or  green  masses  of  fibrous 
structure,  more  or  less  soft  and  silky.  Readily  fusible  into  a  colour- 
less or  pale  greenish  glass.  A  fibrous  variety  of  Amphibole  or  Py- 
roxene. Passes  into  fibrous  serpentine,  but  distinguished  properly 
from  the  latter  by  not  being  decomposed  by  sulphuric  acid,  and  by 
yielding  merely  traces  of  water  in  the  bulb-tube.  Also  by  its  greater 
fusibility. 

(Sp.  gr.  2-9  or  higher.     In  most  cases,  distinctly  over  3'0). 

DIOPSIDE,  and  other  light-coloured  PYROXENES  (Malacolite,  Alalite, 
Sahlite  in  part) :  Average  composition,  MgO  18,  CaO  26,  SiO2  56  ; 
but  in  some  cases  5  or  6  per  cent.  APO3,  and  only  50  or  51  per  cent. 
SiO2  are  present.  Clino-Rhombic  ;  crystals,  as  in  Augite  (see  above), 

commonly  eight-sided  prisms  made  up  of  the  forms  Y,  Y,  and  Y,  and 
terminated  by  several  polar  forms  or  by  a  large  basal  plane.*  Y:Y 

87°  6';  Y:Y  133°  33';  Y:Y  136°  27';  B:Y  105°  30'.  Occurs 
also  abundantly  in  lamellar  and  other  conditions,  with  cleavage 
angles  of  about  87°  and  93°.  Usually  greenish-white  or  some  light 
shade  of  green,  passing  into  deeper  green;  H  5'0-6'0;  G  3'0-3'4. 
BB,  in  thin  splinters,  fuses  more  or  less  readily  into  a  colourless  or 
lightly-tinted  glass. 

TREMOLITE,  and  other  light-coloured  AMPHIBOLES  (Grammatite, 
Actiiiolite  in  part,  Nephrite  in  part,  Smaragdite) :  Average  compo- 
sition, CaO  13*5,  MgO  28-5,  SiO2  58;  but  in  some  varieties  a  small 
amount  of  A12O3  is  present,  with  corresponding  decrease  of  SiO2. 
Many  examples  also  contain  1  or  2  per  cent,  of  fluorine.  Clino-Rhom- 
bic ;  crystals  commonly  oblique-rhombic  prisms  composed  of  the  four 

planes  Y,  with  two  depressed  triangular  planes  or  side-polars  P  at 
each  extremity;  or  sometimes  six-sided,  from  presence  of  Y;  the 

basal  form  B  also  often  present.     Y:Y  124°  30';  Y:Y  117°  45'; 
/     /• 
P  :  P  148°  16'.     Occurs  likewise  very  abundantly  in  fibrous  and 

lamellar  masses,  with  cleavage-angle  of  124°  30';  H  5-0-6-0;  G  2-9- 
3-2 ;  colourless,  but  more  generally  greenish-white  or  some  pale 

*This  plane  is  regarded  by  many  crystallographers  as  a  front-polar  or  hemi-orthodorue.    See 
the  note  on  Pyroxene  at  the  end  of  the  present  Table. 


244  BLOWPIPE    PRACTICE. 

shade  of  green,  passing  into  grass-green  and  other  deeper  shades. 
BB,  in  thin  splinters,  more  or  less  easily  fusible. 

GLAUCOPHANE:  Na2O  7-33,  CaO  2-20,  MgO  13-07,  FeO  5-78, 
APO3  12-03,  Fe203  2-17,  SiO2  57-81.  Clino-Rhombic,  with  Y  on  Y 
(as  in  Amphibole)  124°  30'-125°;  crystals,  mostly  long  flat  prisms, 
vertically  striated,  and  passing  into  fibrous  masses;  H  5 '5-6-5 ; 
G  3-1-3-2  ;  dark  greyish-blue,  bluish-black;  BB,  easily  fusible  into 
a  greenish  glass.  A  rare  species,  hitherto  only  obtained  from  the 
Island  of  Syra. 

ZOIZITE  :  CaO  24,  APO3  30,  SiO2  41,  with  small  amounts  of  MgO 
and  Fe2O3,  and  about  2  per  cent,  of  basic  water,  the  latter  not  revealed 
by  ordinary  ignition  in  the  bulb-tube.  Rhombic  or  Clino-Rhombic  7 
but  crystals  more  or  less  indistinctly  formed ;  commonly  in  bladed 
or  sub-columnar  examples,  longitudinally  striated.  White,  pale-grey, 
pale-greenish,  yellowish,  or  red;  H  6-0;  G  3-1-3-4.  BB,  swells  up, 
emits  a  few  bubbles,  and  melts,  if  in  thin  splinters,  into  a  colourless 
glass.  After  fusion  or  strong  ignition,  is  decomposed  with  gelatini- 
zation  by  hydrochloric  acid,  and  then  shews  in  the  spectroscope  mo- 
mentary red  and  green  Ca-lines.  Thulite  is  a  rose-red  variety,  con- 
taining a  small  percentage  of  Mii203.  Unionite  is  a  white  variety. 

TOURMALINE  :  Black  varieties  (SCHORL)  and  some  Brown  varieties : 
MgO,  FeO,  MnOj  APO3,  B2O3,  SiO2.  Hemi-Hexagonal,  mostly  in 
three-sided  or  nine-sided  prisms,  or  in  fibrous  and  columnar  masses 
of  a  jet-bkck  or  brown  colour;  H  7'0-7'5 ;  G  3-0-3-2.  Fuses 
generally  into  a  black  or  dark  slag,  but  sometimes  into  a  dull- 
yellowish  or  more  or  less  uncoloured  glass  or  enamel.  The  fused 
mass  crushed  to  powder  and  moistened  with  sulphuric  acid  imparts 
a  distinct  green  coloration  to  the  flame-border.  See  above,  under 
A?  tttt. 

YESUVIAN  (Idocrase,  Egeraiie)  :  Average  composition,  CaO  30  to 
34;  MnO,  FeO,  MgO,  5  to  8;  Fe2O3,  A12O3,  18  to  20,  SiO2  37  to 
39,  with  small  amount  of  alkalies  and  basic  H2N.  Tetragonal ; 
crystals,  commonly,  square  prisms  (or  8-sided  prisms  composed  of  the 
two  square  prisms  Y,  Y)  terminated  by  the  pyramid  P  and  a  well- 
developed  base,  B  :  the  latter  form  very  rarely  absent.  B  on  P 
142°  45'  to  142°  57'.  Occurs  also  in  columnar  and  granular  masses; 
H  6-5;  G  3-33-3-45;  dark-brown,  yellowish-brown,  brownish-red, 
yellow,  green  of  various  shades,  rarely  blue.  BB,  melts,  usually 


MINERAL  TABLES  : — XXVI.  245 

with  slight  bubbling,  into  a  lightly-tinted  glass.  This,  when  crushed, 
•dissolves  with  gelatinization  in  hydrochloric  acid,  and  then  shews 
momentary  red  and  green  Ca-lines  in  the  spectroscope.  Cyprine  is  a 
folue  variety  containing  a  small  percentage  of  CuO.  Wiluite, 
Egerane,  Xanthite,  Loboite,  Frugardite,  Heteromerite,  are  other 
varieties.  Colophonite,  in  yellow  or  brown  grains  and  rounded 
masses,  commonly  referred  to  Garnet,  is  also  as  regards  most  examples 
a  Vesuvian.  Practically,  however,  Vesuvian  and  Garnet  can  scarcely 
<be  distinguished  from  each  other,  except  by  their  .crystallization. 

GARNET  :  Light  coloured  varieties  :  CaO,  A12O3,  SiO2,  <fec.  Essen- 
tially in  rhombic  dodecahedrons  or  trapezohedrons,  or  in  rounded 
.grains,  of  a  red,  yellow,  brown,  or  green  colour;  H  T'0-7'5;  G 
3'2-3'8.  More  or  less  readily  fusible  into  a  colourless  or  lightly 
tinted  glass.  See  also  under  ff  and  A2  of  this  Table. 

(Sp.  gr.  under  2~8,  in  most  c.ase-s  about  2*6.     Fusible,  unless  In  fine  splinters, 
on  the  edges  only), 

ORTHOCLASE  (Common  or  Potash  Feldspar) :  K20  16'9,  A12O3 18'4, 
SiO2  64*7,  but,  very  generally,  small  portions  of  Na?O,  <fcc.,  are  also 
present.  Clino-Rhombic  ;  crystals  frequently  flattened  parallel  with 
the  side-vertical  planes,  and  often  extended  in  that  direction;  twins 
^Tery  common:  see  Note  at  end  of  TABLE.  Prism-angle  118°  47'. 
Occurs  also  abundantly  in  cleavable,  lamellar  masses,  the  cleavage 

planes  ( =  B,  V)  meeting  at  right-angles.  H  6'0 ;  G  2'53-2'58 ; 
colourless,  white,  flesh-red,  bright-red,  light-green,  pale-yellowish, 
light-grey ;  somewhat  pearly  on  cleavage- planes  ;  iridescent  in  some 
varieties,  and  occasionally  opalescent.  BB,  fusible  011  the  edges  only, 
unless  in  the  form  of  a  thin  pointed  spliater,  in  which  ease  the 
extremity  is  quickly  rounded  into  a  clear  glass.  Ignited,  and  then 
fused  with  carb.  soda  or  fluor  spar,  or  simply  moistened  with  hydro- 
chloric acid  after  ignition,  shews  in  spectroscope  the  red  K-line  very 
distinctly.  All  other  lines  (derived  from  the  soda  or  fluor  spar)  may 
be  entirely  obliterated  by  the  intervention  of  a  piece  of  blue  glass. 
Adularia,  Sanidine  or  Ryacolite  (often  called  glassy  feldspar),  Peg- 
matolite,  Ac.,  are  varieties.  Loxoclase  is  also  a  variety,  but  resembles 
Oiigoclase  in  composition.  Perthite  is  a  dark  red-brown  iridescent 
mixture  of  Orthoclase  and  Albite,  the  iridescence  derived  from  minute 
scales  of  Iron  Glance. 


246  BLOWPIPE    PRACTICE. 

MICROCLINE  :*  A  potassic  feldspar  closely  allied  to  Orthoclase,  but 
apparently  anortliic  (triciinic)  in  crystallization.  The  cleavage  angle 
only  differs,  however,  from  a  right  angle  by  15  or  16  minutes;  and 
the  prism-angle  (118°  31')  and  other  angles  scarcely  differ  from 
corresponding  angles  in  Orthoclase.  Most  of  the  green  feldspars 
(commonly  called  Amazon  Stone)  are  supposed  to  be  referrible  to 
Microcline ;  but  the  species  (?)  can  only  be  distinguished  from  Ortho- 
clase by  minute  optical  investigation. 

HYALOPHANE  :  A  barytic  feldspar,  almost  identical  with  Orthoclase 
in  crystallization.  G2:8;  white  or  flesh-red.  BB,  tinges  the  flame- 
point  pale-green.  See  under  ff  of  this  section. 

ALBITE  (Soda  Feldspar):  Na2O  11-82,  A12O3  19-56,  SiO2  68-62, 
but  1  or  2  per  cent,  of  the  Na2O  commonly  replaced  by  K2O.  Anor- 
thic ;  but  crystals  generally  clino-rhombic  in  aspect,  and  much  like 
those  of  Orthoclase:  see  Note  at  close  of  Table.  Prism-angle  120° 
47' )  cleavage-angles  86°  24'  and  93°  36'.  Crystals  commonly  in 
twinned  or  compound  forms,  rarely  simple.  Occurs  also  abundantly 
in  lamellar  masses,  with,  cleavage  as  above ;  colourless,  white,  light- 
red,  light-green,  yellowish,  brownish,  &c. ;  H  6-0  (or  6-0-6-5)  ;  G 
2-59-2-64.  BB,  like  Orthoclase,  but  colours  the  flame  more  or  less 
strongly  yellow  :  the  two  species,  however,  can  only  be  distinguished 
by  their  crystallization,  or  by  accurate  chemical  analysis,  although  if 
the  red  K-line  be  distinctly  obtained  in  the  spectroscope,  the  sub- 
stance, as  a  rule,  may  be  safely  -regarded  as  Orthoclase  (or  Microcline). 
-  See  under  Orthoclase,  above.  Pericline  is  a  white  opaque  or  feebly- 
translucent  variety  in  crystals  elongated  more  or  less  in  the  direction 

of  the  right-and-left  axis,  frequently  twinned,  and  strongly  striated 

/ 
on  the  side-vertical  faces  V.     Peristerite  is  a  white,  slightly  iridescent 

variety.     Olafite,  Cleavelandite,  and  Zygadite,  are  other  varieties. 

OLIGOCLASE  (Soda-lime  Feldspar) :  Na20  (slightly  replaced  by 
K2O),  CaO,  A12O3,  SiO2.  Anorthic;  crystals  much  like  those  of 
Albite,  with  prism-angle  120°  42'  to  120°  53',  and  cleavage-angles  of 
about  86°  10'  (or  86°  30'),  and  93°  50'  (or  93°  30').  Principal 
cleavage-plane  (B),  delicately  striated ;  twin-crystals,  very  frequent. 
Occurs  also  in  lamellar  and  fine-granular  masses.  H  6'0;  G  2 '6-2 '66; 
white,  pale-red,  greenish-grey,  &c.,  with  somewhat  waxy  lustre ; 

*  Of  Des-Cloizeaux,  not  Breithaupt.  The  Microcline  of  the  -latter  is  the  iridescent  Orthoclase 
from  the  zircon-syenite  of  Norway. 


MINERAL  TABLES  : — XXVI.  247 

occasionally  iridescent.  BB,  fuses,  in  thin  splinters,  into  a  colourless 
glass.  Apart  from  its  more  ready  fusibility,  this  species  can  scarcely 
be  distinguished  from  Albite,  except  by  actual  analysis. 

(Sp.  gr.  under  2*5.  Compact  structure.  Very  easily  fusible), 
OBSIDIAN  :  K20,  Na2O,  A1203,  SiO2,  with  small  amounts  of  CaO, 
Fe2O3,  &c.  In  amorphous  masses,  breaking  with  conchoidal  fracture 
into  glassy  sharp-edged  fragments.  H  6'0-7'0 ;  G  2'2-24.  Black, 
brown,  grey,  greenish,  <fec.,  sometimes  striped  or  zoned  in  different 
shades ;  translucent  to  opaque.  Easily  fusible  with  bubbling  into  a 
white  glass  or  enamel.  Pitch  stone  is  a  less  vitreous,  coarser  variety. 
Pearlstone  is  a  closely  related  substance,  made  up  essentially  of  small 
pearly  concretions,  or  containing  these  in  a  vitreous  obsidian-like 
paste.  All  are  volcanic  products  :  rather  rocks  than  minerals  proper. 


NOTE  ON  TABLE  XXVI. 

This  Table  consists  entirely  of  silicates,  distinguished  from  other  compounds 
of  that  class  by  being  distinctly  fusible,  and  by  yielding  no  water  (or  merely 
traces)  when  ignited  in  the  bulb- tube.  All  give  the  characteristic  reaction  of 
silicates  by  fusion  with  phosphor-salt — a  silica-skeleton  separating,  whilst  the 
bases  dissolve  in  the'  flux.  In  some  cases,  a  portion  of  the  silica  is  dissolved 
also,  but  this  precipitates  on  cooling,  and  the  bead  becomes  more  or  less 
opalescent  or  clouded.  The  more  commonly  occurring  minerals  of  the  Table 
comprise  representatives  of  the  following  series :  Micas,  Boro- Silicates,  Garnets, 
Epidotes,  Iron  Chrysolites,  Pyroxenes  and  Ainphiboles,  Scapolites,  Feldspars. 

The  Mica  Group,  as  regards  the  present  Table,  is  chiefly  represented  by 
Lepidolite — the  ordinary  micas,  Muscovite,  Phlogopite,  and  Biotite,  being  as 
a  rule  fusible  only  when  in  very  thin  scales,  and  often  on  the  edges  only. 
Hence,  these  latter  species  are  described  in  Table  XXV. ,  and  in  the  Note  to 
that  Table.  Lepidolite  is  easily  recognized  (in  ordinary  examples)  by  its  deli- 
cate red  or  reddish-grey  colour,  and  its  occurrence  in  aggregations  of  soft, 
pearly  scales.  Also  by  its  intumescence  and  ready  fusion  in  the  blowpipe- 
flame,  or  even  in  the  flame  of  the  Bunsen  burner,  and  by  the  crimson  coloration 
which  it  imparts  to  this.  In  the  spectroscope,  the  crimson  Li-line  and  yellow 
Na-line  come  out  at  once  with  great  brilliancy,  but  the  red  K-line  is  generally 
overpowered  by  the  intensity  of  the  lithium  spectrum,  unless  this  be  cut  off 
by  the  intervention  of  a  blue  glass  between  the  spectroscope  and  the  flame. 

The  Boro-silicates  of  this  Table  include  the  dark,  fusible  Tourmalines, 
represented  essentially  by  Schorl,  and  the  anorthic  species,  Axinite.  These, 
however,  have  no  very  close  relations  as  minerals,  beyond  the  presence  in  both 
.of  boracic  acid,  an  exceptional  component.  The  silica  percentage  is  com- 


248  BLOWPIPE    PRACTICE. 

paratively  low,  averaging  38  or  39  in  Tourmaline,  and  about  44  in  Axinite, 
The  boracic  acid  apparently  replaces  alumina. 

Schorl  may  generally  be  distinguished  by  its  jet-black  colour  and  triangular 
cross  fracture.  The  crystals  are  sometimes  simple  three-sided  prisms ;  but 

these  are  bevelled,  in  general,  on  their  vertical  edges — a  combination  of  — 

and  V2  being  thus  formed — and  they  are  usually  terminated  by  the  planes  of 
a  rhombohedron  (R)  with  polar  angle,  i.e.,  angle  over  a  polar  edge,  of  about 
133°  30'.  Frequently  also  the  planes  of  a  second  rhombohedron  (  -  2R)  with 
polar  angle  of  about  103°  or  103°  20',  alternate  with  the  latter ;  and  crystals 
often  shew  dissimilar  forms  at  their  extremities :  see  the  Note  to  TABLE  XXIV. 

Axinite  is  readily  distinguished  by  its  flattened,  sharp-edged,  anorthic 
crystals  (brown,  violet,  pinkish-grey,  in  colour,  or  sometimes  green  from  inter- 
mixed chlorite),  and  by  the  green  coloration  which  it  communicates  -to  the 
blowpipe-flame  during  fusion.  The  crystals  are  essentially  oblique  rhomboidal 
prisms  with  only  the  diagonally-opposite  edges  and  angles  replaced.  The 
prism-angle  equals  135°  31' ;  B  on  one  prism-plane,  134°  45' ;  and  on  the  other 
prism-face,  115°  38'.*  The  two  prism-  planes  are  vertically  striated,  i.e., 
parallel  with  their  combination  edges,  whilst  the  B  plane  is  striated  trans- 
versely. 

The  Garnet  group  is  represented  in  this  Table  by  the  different  varieties  or 
sub-species  of  Garnet  (the  infusible  chrome-garnet  Uwarowite  [TABLE  XXIV.] 
excepted),  and  by  the  related  species  Vesuvian. 

The  specific  name  of  Garnet  includes  a  great  number  of  related  silicates  of 
regular  crystallization  and  common  formula — the  latter,  empirically,  3  HO, 
11203,  3  SiO2.  The  RO  represents  CaO,  MgO,  MnO,  FeO  ;  and  the  R203  equals 
A1'203,  Fe203,  &c.  The  varieties  which  result  from  the  preponderance  of  one 
or  the  other  of  these  isomorphous  bases  necessarily  present  different  colours, 
and,  within  certain  limits,  different  degrees  of  specific  gravity,  t  The  colour 
thus  varies,  as  a  rule,  from  light  tints  of  red,  yellow,  and  green,  through  deep- 
red  and  olive-green  into  brown  and  black ;  and,  occasionally,  colourless 
examples  are  met  with.  The  more  common  garnets  are  dark-red  or  red- 
brown,  and  nearly  or  quite  opaque.  The  average  sp.  gr.  is  about  3 '5  for  the 
lighter  coloured  varieties,  and  3 '9  or  4'0  for  the  dark  garnets,  the  limits  lying 
between  3 '15  and  4  "25  or  4 '3.  The  crystallization  is  comparatively  uniform, 
consisting  essentially  of  the  rhombic  dodecahedron  or  of  the  trapezohedron 
2-2,  or  of  the  two  combined.  In  the  trapezohedron,  the  angle  over  a  long  or 
axial  edge  equals  131°  49'.  In  combination,  the  trapezohedron  replaces  the 
edges  of  the  dodecahedron,  and  thus  presents  a  cruciform  four-planed  point- 

*By  most  German  crystallograpliers  B  is  made  the  face  of  a  tetarto-pyramid,  P.  The  angles 
given  above  are"  those  of  Von  Rath,  but  they  fluctuate  within  30  or  40  minutes  in  crystals  from 
different  localities. 

t  This  latter  character,  however,  does  not  depend  absolutely  on  composition,  as  regards 
minerals  generally.  A  striking  instance  is  afforded  by  ordinary  Iron  Pyrites  and  Copper 
Pyrites.  The  former,  consisting  of  Fe  46'67,  S  53'33,  has  an  average  sp.  gr.  of  5'0;  whilst  the 
latter,  with  less  sulphur  (34 '9  ,  and  with  the  heavier  metal  copper  forming  part  of  the  base 
(Cu  34 '6,  Fe  30'5),  shews  a  maximum  density  of  only  4/3. 


MINERAL  TABLES  : XXVI.  249 

ment  at  each  pole  of  the  crystal.     Occasionally  also,  the  edges  of  the  rhombic 
dodecahedron  are  bevelled  by  the  planes  of  the  adamantoid  3-f  or  4-f . 

Vesuvian  or  Idocrase  closely  resembles  Garnet  in  general  composition,  and 
until  recently  the  two  were  thought  to  present  the  same  atomic  constitution. 
This  is  probably  not  the  case,  although  the  formula  of  Vesuvian  is  still  doubtful. 
But  the  two  minerals  apart  from  crystallization  are  evidently  nearly  allied. 
The  more  common  crystals  of  Vesuvian  are  composed  of  the  two  square  prisms 
V  and  V,  striated  longitudinally,  and  terminated  by  a  square  pyramid,  P, 
more  or  less  deeply  truncated  at  the  apex  by  the  basal  form  B.  Frequently 
the  vertical  edges  of  V  are  bevelled  by  the  planes  of  an  octagonal  prism  V2  or 
V3  ;  and  the  polar  edges  of  the  pyramid  are  replaced  by  a  front-polar  or  front- 
pyramid  R  Angular  measurements  are  slightly  variable,  but  average  as 
follows  :  P  :  P  over  polar  edge  129°  29',  over  middle  edge  74°  14' ;  B  :  P 
142°  53' ';  P  :  Fover  polar  edge  141°  1',  over  middle  edge  56°  8'  j  B  :  P  151°  56'. 
For  other  characters,  see  the  Table. 

The  Epidote  Group  is  represented  in  the  Table  by  Epidote,  Zoizite,  and 
Allanite  or  Orthite.  The  latter  in  most  examples  is  decomposed  with  gelati- 
nization  by  hydrochloric  acid,  and  is  black  and  almost  sub-metallic  in  aspect. 
Commonly  in  columnar  and  fine-granular  masses  jjnore  rarely  in  clino-rhombic 
crystals,  with  V  :  V  70°  48'  and  109°  12' ;  V  :  V  125°  24' ;  and  B  :  V  115°. 
This  latter  is  also  the  cleavage-angle,  but  the  cleavage  is  very  indistinct. 
Zoizite  and  Epidote  are  not  decomposed  by  hydrochloric  acid  until  after 
fusion,  when  they  also  gelatinize.  Zoizite  is  light- coloured,  mostly  grey  or 
greyish-white*,  and  chiefly  in  columnar  masses.  Its  crystallization,  long  con- 
sidered identical  with  that  of  Epidote,  is  now  regarded  as  Rhombic,  but 
crystals  are  rare  and  more  or  less  indistinctly  formed.  Epidote  is  usually  dis- 
tinctly coloured,  the  tints  ranging  from  light  yellowish-green  to  dark  green, 
brown,  and  black.  Many  examples  are  fibrous  and  acicular,  and  closely 
resemble  examples  of  pyroxene  and  arnphibole,  and  also  schorl.  From  these, 
however,  Epidote  is  readily  distinguished  by  its  peculiar  reaction'under  the 
blowpipe.  In  place  of  forming  a  single  bead  or  fused  globule,  it  swells  up 
into  a  cauliflower-like  mass,  the  separate  portions  of  whiten  become  rounded, 
but  cannot  with  ordinary  blowing  be  brought  into  a  bead,  properly  so  called. 
Crystals  are  of  frequent  occurrence.  They  are  clino-rhombic,  and  practically 
identical  with  those  of  Orthite,  but  are  not  easily  made  out  by  the  unpractised 
eye.  In  their  conventional  position,  they  form  transversely  elongated  prisms, 
the  extension  being  in  the  direction  of  the  ortho -diagonal  or  right-and-left 
axis,  with  usually  two  (or  several)  inclined  planes  at  the  side.  The  horizon- 
tally extended  planes  usually  comprise  the  basal  plane  B,  and  the  front-vertical 
V,  with  interfacial  angle  (which  is  also  the  cleavage  angle)  of  1 15°  24'.  In  the 
same  zone  with  these  planes,  several  intermediate  planes  (the  faces  of  front  or 
ortho-polars)  also  frequently  occur  ;  and  in  most  cases  the  planes  of  this  zone 
are  striated  parallel  with  their  combination- edges.  The  more  common  forms 
of  the  zone  are  B  (the  chief  cleavage-plane),  V  (the  second  cleavage-plane), 
and  P  ;  with  consecutive  interfacial  angles  of  115°  24'  as  stated  above,  128°  18', 
and  116°  18'.  The  two  predominating  planes  at  the  lateral  ends  of  the  crystal 


251J  BLOWPIPE    PRACTICE. 

are  sometimes  the  prism-planes  V,  with  angles  of  110°  on  adjacent  faces,  and 
70°  in  front  or  over  V,  and  125°  on  V.  In  other  crystals,  these  end  planes  are 
those  of  the  hemi-pyramid  P,  and  they  meet  at  an  angle  of  109°  35'.  Both  V 
and  P  are  also  sometimes  present  together,  meeting  at  angles  of  150°  57'  and 
117°  40'.  Twin  combinations,  with  twin-face  parallel  to  V,  are  of  frequent 
occurrence. 

The  so-called  Iron  Chrysolites  are  represented  by  Fayalite,  Hyalosiderite, 
and  Lievrite  or  Ilvaite,  the  latter,  only,  of  general  occurrence.  This  species, 
by  its  black  colour  and  general  aspect  somewhat  resembles  Orthite.  Like 
Orthite  also,  it  melts  readily  into  a  black  magnetic  glass,  and  is  decomposed 
with  separation  of  gelatinous  silica  by  hydrochloric  acid.  The  crystallization 
however  is  Rhombic,  and  the  crystals  are  elongated  vertically.  In  most 
cases  they  are  eight-sided  prisms,  composed  of  the  two  rhombic  prisms  V  and 

V2,  terminated  by  the  four  planes  of  a  rhombic  pyramid  P,  the  front  polar 
edges  of  which  are  replaced  by  a  plane  of  the  form  P.  The  chief  angles  are  as 

follows  :  V  :  V  112°  38' ;  V2  :  V2  106°  15' ;  P  :  P,  over  front  edge_or  over  P3 
117°  30' ;  over  side  edge  139°  30' ;  over  middle  edge  77°  12' ;  P  :  P,  over  sum- 
mit, 11 2°  49'.  The  prisms,  in  general,  shew  strong  vertical  striae,  indicating 
additional  prismatic  forms,  V£,  &c. ;  and  crystals  thus  affected  often  become 
more  or  less  cylindrical,  and  pass  into  columnar  masses. 

The  Pyroxene  series  comprises  a  group  of  species  and  sub-species  (essentially 
bisilicates  of  RO,  typically  MgO,  FeO,  CaO)  in  which  the  crystallization  is 
either  Clino-Rhombic  or  Rhombic,  with  the  chief  prism-angle  and  cleavage- 
attgle  approximating  to  87°  (or  its  supplement  93°).  The  Rhombic  species 
comprise  Enstatite,  with  Bronzite  and  Hypersthene.  The  typical  Clino- 
Rhombic  forms,  in  which,  as  in  the  Rhombic  group,  alumina  is  either  absent 
or  only  subordinately  present,  include  Pyroxene  proper,  with  Acmite  and 
other  rarer  species  ( Jeffersonite,  &c. ) ;  and  also  the  manganese  species, 
Rhodonite,  and  the  more  or  less  aberrant  Wollastonite,  the  latter  a  purely 
calcareous  species  differing  essentially  from  the  ordinary  pyroxenes  by  being 
readily  decomposed,  with  separation  of  gelatinous  silica,  in  hydrochloric  acid. 
The  lithia-holding  and  aluminous  Spodumeiie  or  Triphane  is  also  commonly 
referred  to  the  Pyroxene  group  from  its  cleavage-angle  and  lately  determined 
crystallization  ;  but  its  composition  (Li20  4*5  to  6  "5,  APO3  25 '3  to  29,  SiO2  63 
to  66)  and  its  general  aspect,  are  more  feldspathic  than  augitic.  The  prism- 
angle  (and  corresponding  cleavage-angle)  V  :  V,  scarcely  differs  from  the 
principal  cleavage-angle  in  Albite.  Its  distinctive  characters,  and  those  of  the 
other  minerals  of  the  group,  are  given  sufficiently  in  the  Table,  but  some 
additional  remarks  on  the  commonly  occurring  species  Pyroxene  are  here 
appended.  This  species  is  commonly  subdivided  into  Non-aluminous '  and 
Aluminous  Pyroxene.  The  non-aluminous  pyroxenes  (apart  from  the  ferrugi- 
nous sub-species  Hedenbergite)  are  chiefly  of  a  light  colour,  and  the  aluminous 
varieties,  mostly  (though  not  exclusively)  deep-green  or  black,  and  more  or 
less  ferruginous  ;  but  even  in  these,  the  alumina  is  always  under  10,  and 
generally  under  7,  per  cent.  The  old  name  of  Diopside  may  serve  conveniently 


MINERAL  TABLES: — XXVI.  251 

to  include  all  the  light-coloured  non-aluminous  pyroxenes  (Malacolite,  Alalite, 
&c.),  and  that  of  Augite  to  denote  the  dark  and  generally  aluminous  varieties. 
In  both  diopside  and  augite  the  crystals  are  prismatic  and  essentially  eight- 
sided,  or  (as  regards  these  prismatic  planes)  made  up  of  the  four  planes  of  the 
rhombic  prism  V,  truncated  on  its  obtuse  vertical  edges  by  the  two  planes  of 
the  Front- Vertical  V,  and  on  its  acute  edges  by  the  Side- Vertical  or  Clino- 

Vertical  V.  The  prism-angle  in  front  equals  87°  6' ;  V  on  V  of  course  equals 
90° ;  and  V  on  V7  133°  33'.  But  apart  from  these  vertical  planes,  Pyroxene 
crystals  present  three  more  or  less  distinct  types.  In  one,  common  to  both 
light  and  dark  varieties,  the  crystals  are  simply  8-sided  prisms  terminated  by 
the  basal  plane,  *  with  B  on  V  equal  to  105°  30'.  These  crystals  are  sometimes 
flattened  parallel  to  V  (the  ortho-pinakoid) ;  but  in  general  they  are  remark- 
ably symmetrical,  and  as  the  pinakoids  or  Front  and  Side  Verticals,  V  and  V, 
which  meet  at  right  angles,  frequently  preponderate,  this  type  of  crystal  looks 
remarkably  like  a  square  prism  with  truncated  vertical  edges.  In  the  second 
type,  especially  characteristic  of  augite,  proper,  the  crystals  are  almost  invari- 
ably flattened  parallel  with  V,  and  are  surmounted  by  the  two  planes  of  the 

clinodome  or  side-polar  P,  meeting  over  the  summit  at  an  angle  of  120°  48'.  "\ 
In  this  type,  the  base  is  also  occasionally,  but  only  subordinately,  present, 
together  with  other  slightly  developed  polar  forms  ;  and  its  crystals  are  often 
twinned  parallel  with  V.  The  crystals  are  then  terminated  by  four  planes, 
and  shew  re-entering  angles  at  one  extremity.  In  the  third  type,  the  crystals 
are  largely  terminated  by  the  planes  of  a  hemi-pyramid,  with  angle  over  front 
polar  edge  of  95°  48',  a  second  hemi-pyramid,  with  front  angle  of  131°  30'', 
often  appearing  at  the  lower  extremity.  Other  combinations  occur,  but  are 
comparatively  rare. 

The  Amphiboles  form  a  parallel  series  with  the  Pyroxenes,  and  like  the 
latter  are  essentially  bisilicates  of  CaO  and  MgO,  with  part  of  these  bases 
replaced  in  dark  varieties  by  FeO  ;  and  with  APO3  (5  to  15  per  cent. )  frequently 
replacing  a  portion  of  the  silica,  the  latter  in  non-aluminous  amphiboles  vary- 
ing from  about  55  to  59  per  cent.,  and  in  aluminous  varieties  from  39  to  49 
per  cent.  Small  amounts  of  fluorine  and  alcalies  are  also  commonly  present, 
especially  in  the  darker  amphiboles  ;  and  magnesia  always  exceeds  lime  in  the 
base,  whereas  in  the  pyroxenes  the  lime  predominates.  Corresponding  varieties 
shew  in  amphibole  a  slightly  lower  sp.  gr.  than  in  pyroxene  ;  but,  practically, 

*  By  German  and  many_other  crystallographers  this  is  not  regarded  as  the  base,  but  as  an 
orthodome  or  front-polar  P.  By  making  it  the  base,  however,  the  two  sloping  planes  by  which 

the  common  augite  crystals  are  always  terminated,  become  clinodomes  or  side-polar  planes  P, 
in  place  of  being  the  planes  of  a  hemi-pyramid  P;  and  in  that  manner,  as  pointed  out  by  VON 
RATH,  the  correspondence  between  pyroxene  and  amphibole  crystals  is  rendered  much  more 
apparent.  This  view  has  been  always  held  by  French  crystallographers,  and  is  recommended 
by  its  greater  simplicity.  It  was  departed  from,  apparently,  in  the  first  instance  by  German 
crystallographers  in  order  to  obtain  an  imaginary  Grundform  or  triaxial  pyramid. 

t  See  the  preceding  foot  note.  These  terminal  planes  are  regarded  by  most  German  crystailo- 
graphers  as  the  planes  of  a  hemi-pyramid,  P, 


252  BLOWPIPE    PRACTICE. 

the  two  species  can  only  be  distinguished  by  their  crystallization  and  cleavage- 
angles.  In  Amphibole  proper,  two  leading  varieties'  or  sub-species  may  be 
recognized.  Tremolite  or  Grammatite,  including  all  the  white,  grey,  and  pale- 
green  amphiboles  ;  and  Hornblende,  including  the  deep-green,  dark-brown  and 
black  kinds.  These  are  connected  by  the  variety  known  as  Actynolite,  which 
presents  a  more  or  less  bright-green  colour,  and  usually  occurs  in  fibrous 
masses  and  long  prismatic  crystals  and  aggregations.  These  forms  are  also 
generally  presented  by  Tremolite  ;  whilst  Hornblende  is  usually  in  dark-green 
lamellar  or  granular  masses,  or  in  thick  crystals  (commonly  known  as  Basaltic 
Hornblende)  of  a  dark-brown  or  black  colour.  The  System,  as  in  Pyroxene, 
is  Clino-Hhombic,  and  viewed  generally,  amphibole  crystals  present  three 
leading  types.  The  first  and  simplest  type  is  comparatively  rare.  It  consists 

of  an  eight-sided  -prism  composed  of  the  vertical  forms  V,  V,  and  V,  terminated 
by  a  large  basal  plane ;  and  it  thus  represents  the  simple  Pyroxene  type 

described  under  that  species.  V  :  V=  124°  30' ;  V :  V  1 17°  15' ;  B  :  V  104°  50'. 
A  second  and  much  commoner  type  consists  of  a  six-sided  prism  composed  of 
the  rhombic  prism  V  (with  angle  as  above)  truncated  on  its  acute  vertical 

edges  by  the  form  V,  and  terminated  by  two  nearly  flat  side-polar  planes  P, 
meeting  at  an  angle  of  148°  16'.  Sometimes,  also,  the  base,  in  the  form  of  a 
narrow  plane,  replaces  the  common  edge  of  these  terminal  planes ;  and 
occasionally  the  prism  is  eight-sided  from  the  presence  of  V  ;  but  this  front- 
vertical  form,  so  characteristic  of  Pyroxene  crystals,  is  comparatively  rare  in 

Amphibole.     The  third  type,  exhibited  especially  by  the  so-called  Basaltic 

/ 
Hornblende,  consists  of  a  six-sided  prism,  composed  of  V  and  V  (with  planes 

of  practically  equal  width),  surmounted  by  three  rhombiform  planes,  consist- 
ing of  two  planes  of  a  hemi-pyramid  P,  and  the  basal  plane  B — these  three 
terminal  planes  being  also  in  general  of  equal  or  nearly  equal  size.  A 
marked  pseudo-hexagonal  aspect  is  thus  imparted  to  the  crystal.  P :  P 
148°  30',  P :  B  145°  35'.  Other  polar  forms  are  sometimes  subordinately  pre- 
sent ;  and  the  crystals  of  this  type  are  frequently  twinned  parallel  to  the 
position  of  the  front-vertical  V.  In  these  twins  there  is  no  re-entering  angle, 
but  the  four  planes  of  the  hemi-pyramid  P  are  brought  together  at  one  end  of 
the  crystal,  and  the  two  B  planes  at  the  other.  The  iuterfacial  angle  of  the 
Basal  planes,  thus  brought  together,  equals  150°  20'. 

The  Scapolites  are  essentially  lime-alumina  silicates  of  Tetragonal  crystalli- 
zation. They  have  been  separated  into  various  species  or  sub-species,  but  a]l 
may  fairly  be  referred  to  a  single  representative,  Scapolite  proper  or  Wernerite. 
In  this  species,  the  crystals  consist  commonly  of  combinations  of  the  two 
square  prisms  V  and  V,  forming  an  eight-sided  prism,  terminated  by  the  four 
planes  of  the  pyramid  P,  or  by  those  of  P  and  P,  the  common  summit  of  these 
being  frequently  truncated  by  the  basal  form  B.  The  angles  fluctuate  some- 
what in  different  varieties,  but  average_as  follows^  Bj^P  148°  9' ;  P :  P  over 
polar  edge  136°  11' ;  P :  V  121°  51' ;  B  :  P~  156°  14' ;  P  :  P  over  polar  edge  147°. 
In  addition  to  these  forms,  many  crystals  shew  an  octagonal  prism  V2  (slightly 


MINERAL  TABLES  : XXVI.  253 

developed),  and  an  octagonal  pyramid  3P3,  but  these  are  usually  in  a  hemi- 
hedral  condition.  Many  crystals,  again,  are  much  distorted  from  inequalities 
in  the  size  of  corresponding  planes.  Apart  from  its  crystallization,  Wernerite 
is  distinguished  from  light- coloured  Pyroxenes  and  Amphiboles  by  its  lower 
specific  gravity  (2 '6  to  2 '8,  in  place  of  2 '9  to  3 '4),  and  by  its  partial  decom- 
position in  hydrochloric  acid.  From  the  Feldspars  it  differs  essentially  by  its 
want  of  sharply- defined,  smooth  and  lustrous  cleavage-planes,  and  by  its  ready 
fusion.  The  more  typical  feldspars,  moreover,  Orthoclase  and  Albite,  are  not 
attacked  by  hydrochloric  acid. 

The  Feldspars  are  essentially  aluminous  silicates  of  potash,  soda,  or  lime, 
characterized  by  the  general  absence  of  iron  oxides  and  magnesia,  by  their 
light  coloration,  their  non-fibrous,  cleavable  structure,  the  latter  an  especially 
salient  character,  and  by  their  clino-rhombic  or  triclinic  (anorthic)  crystalli- 
zation. As  a  rule,  they  are  difficultly  fusible,  and  the  lime  species  only  are 
decomposed  by  acid.  In  the  more  typical  or  alcaline  feldspars,  the  amount  of 
silica  exceeds  60  per  cent.  It  is  now  very  generally  thought  that  three  species 
only  of  feldspar  should  be  admitted,  viz. :  the  potassic  species  Orthoclase,  the 
soda  species  Albite,  and  the  lime  species  Anorthite,  the  other  so-called  species 
being  regarded  as  isomorphous  mixtures  or  combinations  of  these.  This  view 
is  probably  correct,  but  in  the  present  state  of  our  knowledge  it  seems  neces- 
sary to  recognize  (as  in  the  Table)  the  following  compounds  as  constituting 
distinct  feldspathic  types :  The  potash  feldspars  Orthoclase  and  Microcline  ; 
the  baryto-potassic  feldspar  Hyalophane ;  the  soda  feldspar  A  Ibite  ;  the  soda  - 
lime  feldspar  Oligoclase  (including  Andesine) ;  the  lime-soda  feldspar  Labra- 
dorite ;  and  the  lime  feldspar  Anorthite.  The  more  distinctive  characters  of 
these  are  given  fully  in  the  Table ;  but  some  additional  remarks  on  the 
crystallization  of  the  two  more  important  species  Orthoclase  and  Albite  are 
here  appended. 

Orthoclase  crystals  fall  under  three  comparatively  distinct  types.  The 
crystals  of  the  first  or  simplest  type  are  short  rhombic-prisms  terminated  by 
two  sloping  planes.  The  latter  are  frequently'of  nearly  similar  size  and  shape, 
but  consist  of  the  base,  B,  and  a  hemi-orthodome  or  ortho-polar  P,  of  course 
in  alternate  positions.  V :  V  118°  47' ;  B  :  P  129°  43' ;  B  :  V  112°  13' ;  P  :  V 
110°  41'.  P  is  often  transversely  striated,  and  is  sometimos  much  larger  than 
B,  in  which  case  its  planes  resemble  the  V  planes  -in  shape,  and  the  crystal 
has  much  the  aspect  of  a  truncated  rhombohedron.  Occasionally,  the  side- 
vertical  V  is  also  present.  This  type  frequently  occurs  in  twin  forms,  with 
twin-face,*  a  face  of  B.  It  might  be  termed  the  Adularia  or  St.  Gothard 
type.  Its  crystals  are  in  general  more  or  less  translucent,  and  are  always  in 
druses  or  attached  to  the  sides  of  clefts  and  cavities  of  the  rocks  in  which  they 
occur.  In  the  se^  oud  or  Baveno  type,  the  crystals  are  usually  six-sided  prisms, 

composed  of  four  V  planes  and  the  two  planes  of  the  side  or  clino- vertical  V, 
terminated  by  the  basal  plane  and  a  second  ortho-dome  or  ortho-polar  2P. 

*  Throughout  these  notes,  the  terra  "twin-face"  always  denotes  the  face  or  plane  of  junction 
of  the  united  crystals. 


254  BLOWPIPE    PRACTICE. 

These  crystals,  as  a  rule,  are  greatly  elongated  in  the  direction  of  the  clino- 

diagonal,  and  thus  the  two  B  planes  and  the  two  V  planes  become  drawn  out 
backwards  and  upwards,  so  as  to  mask  the  true  symmetry  of  the  crystal  to 
an  unpractised  eye.  V  :  V  and  B  :  V,  as  above  ;  V :  2P  134°  20' ;  B  :  2P 

99°  38' ;  B  :  V  90°.  The  cleavage  is  parallel  to  the  latter  planes.  Very  fre- 
quently the  edges  between  B  and  V  are  replaced  by  the  side-polar  or  clino- 

dome  2P,  the  planes  of  the  latter  inclining  on  B  and  V  at  angles  respectively 

of  135°  4'  and  134°  56'.     Occasionally  also,  the  vertical  edges  between  V  and 
/  / 

V  are  replaced  by  the  planes  of  the  prism  V3.     Crystals  of  this  type  occur  very 

commonly  in  twins,  with  the  twin-face  a  plane  of  the  side-polar  or  clino-dome 

2P.  In  these  crystals,  consequently,  two  long  B  planes,  and  two  long  V 
planes,  come  together,  and  the  crystals  are  rectangular  in  aspect.  In  other 
twins — with  marked  re-entering  angle — the  basal  plane  is  the  twin-face  or 
plane  of  junction.  These  crystals  are  sometimes  translucent,  but  are  com- 
monly opaque,  and  are  often  rough  or  dull  on  their  external  surfaces.  Crys- 
tals of  the  third  or  Carlsbad  type  possess  the  same  forms  as  those  of  the  pre- 
ceding type,  but  present  a  very  different  aspect  from  the  predominance  of  the 

side- vertical  planes  V,  and  the  apparent  flattening  of  the  crystals  parallel  with 
these.  The  elongation  moreover  is  essentially  vertical.  Simple  crystals  are 

much  less  common  than  interpenetrating  twins,  with  twin-face  parallel  with  V. 
These  crystals  are  always  imbedded,  and  they  are  commonly  quite  opaque  and 
more  or  less  rough  and  dull.  Very  often  they  are  partially  altered  into 
Kaolin,  and  sometimes  into  impure  Calcite,  without  change  of  form ;  and  in 
Cornwall,  tin-stone  pseudomorphs  have  assumed  their  shape.  A  fourth  type 
is  presented,  according  to  Gustav  Rose,  by  the  orthoclase  twins  from  the 

syenite  of  southern  Norway,  in  which  the  form  V  fails,  and  the  crystals  are 
united  parallel  to  the  ortho-vertical  V. 

In  Albite,  simple  crystals  are  of  rare  occurrence.  Crystals  which  appear  to 
be  simple,  are  in  most  cases  really  compound,  as  shewn  by  the  striation  of  the 
basal  plane.  One  of  the  more  common  combinations  consists  of  a  six-sided 

prism  composed  of  the  three  forms  V,  (V),  and  V,  terminated  by  three  other 

forms,  the  base  B,  a  front  polar  (P),  an  I  a  tetarto-pyramid  (P) :  each  of  these 
six  forms,  of  course,  consisting  of  a  pair  of  opposite  planes  only.  When  the 

X 

crystal  is  in  position,  B  appears  at  the  top  in  front,  and  (P)  and  (P)  at  the 
back  ;  these  positions  being  necessarily  reversed  as  regards  the  bottom  of  the 

crystal.  V  :  (V)  120°  47' ;  B  :  (P)  52°  17'  and  127°  43' ;  B  :  V  86°  24'  and 
93°  36'  (=  the  cleavage  angles) ;  B  :  V  110°  50' ;  B  :  (V)  114*  42.  The  side- 
vertical  planes  V  commonly  preponderate  and  impart  a  flattened  appearance 

/ 
to  most  crystals.     In  the  more  common  twins,  two  B  planes,  two  V  planes, 

and  two  (P)  planes  come  together.     The  re-entering  angle  between  B  and  B 


MINERAL  TABLES  : — XXVI.  255 

equals  172°  48',  and  these  planes  are  delicately  or  strongly  striated.     Double 

or  multiple  twins  of  this  character,  with  two  B  planes  and  two  (P)  planes 
alternating  at  both  extremities  of  the  crystal,  are  not  uncommon. 

In  the  variety  of  Albite  known  as  Pericline  the  crystals  are  more  or  less 

elongated  in  a  transverse  or  right-and-left  direction,  but  the  interfacial  angles 

\ 
are  practically  identical  with  those  given  above.     The  forms  B  and  (P)  pre- 

/ 
dominate,  and  the  short,  side-vertical  planes  V  are  strongly  striated  ;  but  the 

striae  arise,  here,  from  an  oscillation  between  the  latter  form  and  another  ver- 
tical prism  V3,  the  planes  of  which  occasionally  replace  the  combination  edges 

N 

of  V  and  V,  or  V  and  (V).     In  the  twinned  Periclines,  the  plane  of  junction 
is  parallel  to  the  base. 


[236] 


TABLE    XXVII. 

[Lustre  nou-metallic.     Slowly  attacked  or  only  in  part  dissolved,  BB,  by 
phosphor-salt.     Fusible.     Yielding  water  on  ignition]. 

A. — Fusion-product,  magnetic.* 

AW  DECOMPOSED  WITH  GELATINIZATION  BY  HYDROCHLORIC  ACID. 

t  In  masses  of  essentially  leafy  or  scaly  structure,  or  in  crystals  with 
marked  basal  cleavage.     Hardness  less  than  that  of  calcite. 

CRONSTEDITE:  MgO,  MnO,  FeO,  Fe2O3,  SiO2,  H20  (10  to  12  per 
cent.).  Henri-Hex. ;  crystals  very  small,  often  acicular,  mostly  very 
acute  rhombohedrons  and  scalenohedrons  with  basal  plane ;  cleavage 
parallel  to  the  latter ;  in  thin  leaves  somewhat  flexible ;  also  in  radi- 
ated-fibrous  examples.  H  2*5  ;  G  3 -3-3 -3  ;  black  ;  streak,  dark-green. 
Fusible  with  intumescence  into  a  black  magnetic  bead.  Sideroschi- 
zolite  is  identical  or  closely  related.  In  both,  the  crystal-planes 
shew  a  strong  tendency  to  curvature,  and  in  Cronstedite  the  R  planes 
are  longitudinally  striated. 

YOIGTITE  (Altered  Biotite?) :  CaO,  MgO,  FeO,  Fe203,  A1203,  SiO2, 
H20  (9  per  cent.).  In  green  or  dark-brown  scaly  and  foliated  ex- 
amples, resembling  an  ordinary  dark-coloured  mica.  Fusible  into  a 
black,  more  or  less  magnetic  bead. 

THURINGITE  :  MgO,  MnO,  FeO,  Fe203,  A1203,  SiO2,  H2O  (10  to 
12  per  cent.).  In  dark-green,  scaly -granular  and  micaceous  masses, 
with  greyish-green  streak  and  pearly  lustre.  H  2-0-2-5;  G  3-1-3-2. 
Fusible  into  a  black,  magnetic  bead.  Owenite  is  identical  or  closely 
related. 

METACHLORITE  :  FeO,  A1203,  SiO2,  H20.  In  dark-green,  radiated, 
leafy  masses,  resembling  ordinary  Chlorite,  but  differing  by  its  larger 
percentage  of  FeO,  and  by  gelatinizing  in  hydrochloric  acid. 

f  f  Occurring  in  earthy  or  uncrystalline  masses. 
CHAMOISITE  (Ohamosite) :    FeO,   A12O3,  SiO2,   H2O,  often  mixed 
with  calcite,   &c.     In   dark-green   or   greenish-black,    fine-granular, 

*The  minerals  of  this  subdivision  are  for  the  greater  part  of  more  or  less  indefinite  compo- 
sition. Very  few  can  be  ranked,  properly,  as  distinct  species.  In  most  cases,  therefore,  only 
their  essential  components  are  stated  in  the  Table.  As  a  rule,  lime  is  not  present  normally  in 
these  minerals,  but  many,  after  prolonged  ignition,  shew  a  calcium  spectrum  from  the  presence 
of  intermixed  calcite. 


MINERAL    TABLES  : — XXVII.  257 

oolitic,  or  earthy  masses ;  H  2-0-3-0  ;  G  3-0-34.  Easily  fusible  into 
a  magnetic  bead.  Gelatinizes  in  hydrochloric  acid. 

LILLITE:  FeO,  Fe203,  SiO2,  IPO  (about  11  per  cent.).  In  black- 
ish-green, earthy  rounded  masses ;  H  2-9;  G  3'04.  BB,  fuses  with 
difficulty  into  a  dark  magnetic  slag.  Gelatinizes  in  hydrochloric 
acid. 

PALAGONITE  :  CaO,  MgO,  APO3,  Fe2O3,  SiO7,  H2O.  In  granular 
masses  of  a  yellow  or  dark-brown  colour  and  vitreo-resinous  lustre  ; 
streak,  dull  yellow;  H  3-0-5-0;  G  2-4-2-6.  Easily  fusible  with  in- 
tumescence into  a  more  or  less  magnetic  bead.  Rapidly  decomposed 
by  hydrochloric  acid,  with  separation  of  gelatinous  silica,  as  regards 
most  examples. 

f  f  f  In  distinct  crystals  or  in  fibrous  and  columnar  masses  which 

scratch  glass  readily. 

ILVAITE;  ORTHITE  :  See  TABLE  XXVI.  Some  examples,  only,, 
evolve  traces  of  water  on  ignition. 

A*.- DECOMPOSED  BY  HYDROCHLORIC  ACID,  WITH  SEPARATION  OF  SCALY 
OR  GRANULAR  SILICA. 

t  In  leafy  or  scaly  masses,  or  in  tabular  or  prismatic  crystals  with 
marked  basal  cleavage. 

CHLORITE  (Aphrosiderite  and  other  essentially  ferruginous  vari- 
eties): MgO,  FeO,  Fe2O3,  APO3,  SiO2,  H2O  (about  9  to  12  per  cent.).. 
In  tabular  (Hexagonal)  crystals,  and  in  foliated  and  fine-scaly  masses,, 
of  a  dark  or  bright-greon  colour;  H  1-1-5  ;  G  2'75-2'95.  BB,  melts. 
as  a  rule  on  the  edges  and  surface,  only,  into  a  dark  magnetic  slag. 
Strigovite  is  closely  similar  in  general  characters ;  but  its  sp.  gr.  i& 
slightly  lower,  2-59,  and  its  water  percentage  equals  14-80  according 
to  "Websky's  analysis.  Delessite  is  another  dark-green  chloritic  min- 
eral, occurring  in  scaly  and  fine-fibrous  masses  and  coatings  in  amyg- 
daloidal  traps. 

ASTROPHYLLITE  (Titaniferous  Mica):  In  golden  or  bronze-yellow 
foliated  masses,  often  radiately  grouped,  and  in  tabular  Clino-Rhom- 
bic  crystals ;  H  3 -5.  Most  examples  yield  only  traces  of  water  on 
moderate  ignition.  See  TABLE  XXVI.,  page  228. 

PYROSMALITE:  Essential  components — MnO,  FeO,  SiO2,  ITO 
(about  8  percent.),  Cl.  Hexagonal :  crystals  mostly  six-sided  prisms 
or  tables  with  strongly-marked  basal  cleavage ;  occurs  also  in  granu- 
18 


258  BLOWPIPE    PRACTICE. 

lar  masses ;  brown,  dark-green,  with  metallic-pearly  lustre  on  cleav- 
age plane;  H  4-0-4-5;  G  3-0-3-2.  In  bulb-tube  yields  water,  and 
on  stronger  ignition,  yellow  drops  of  ferrous  chloride.  BB,  fuses 
easily  into  a  steel-grey  or  black  magnetic  globule. 

f  f  In  granular,  fibrous,  or  earthy  masses. 

PALAGONITE  :  In  granular,  vitreo-resinous  masses,  of  a  yellow  or 
brown  colour  with  dull-yellow  streak.  Commonly  gelatinizes  in 
hydrochloric  acid,  but  some  examples  are  decomposed  without  gela- 
tinization.  See  above,  page  257. 

DELESSITE  :  In  dark-green  scaly  and  short-fibrous  masses  and  coat- 
ings in  amygdaloidal  trap.  See  above,  under  Chlorite. 

ANTHOSIDERITE  :  Fe2O3,  SiO2,  H2O  (about  3-6  per  cent.).  In 
tough,  fibrous  masses  of  ochre-yellow  or  brown  colour,  associated 
with  magnetic  iron  ore.  H  6*5 ;  G  about  3'0.  BB  fuses  with  diffi- 
culty to  a  grey  magnetic  slag. 

XYLOTILE  (Mountain  Wood,  &c.):  MgO,  Fe2O,  SiO2,  H2O  (about 
10  per  cent.).  In  light-brown  or  dark-brown  fibrous  or  ligniform 
masses  ;  H  1-5-2-5  ;  G  1-5-2-6,  commonly  about  2-2.  Some  examples 
melt,  BB,  quite  easily,  others  with  difficulty,  to  a  more  or  less  mag- 
netic bead.  Mountain  Cork  is  a  related  substance ;  also  Xylite ; 
but,  in  all,  the  composition  is  indefinite.  Some  varieties  do  not  give 
BB,  a  magnetic  product.  Others  are  scarcely  attacked  by  hydro- 
chloric acid, 

HISINGERITE  (Thraulite) :  Essential  components — FeO,  Fe203,  SiO2, 
HaO  (19  to  22  per  cent.),  with  small  amounts  of  MgO,  A12O3,  &c. 
In  rounded  masses  with  rough  surface  and  compact  structure,  con- 
choidal  in  fracture,  and  pitch-black  colour,  with  brown  or  greenish 
streak  ;  H  3 -0-4-0  ;  brittle ;  G  2-6-3-1 ;  BB  melts  difficultly  (in  some 
cases  on  the  edges  only)  into  a  grey  or  dark  magnetic  slag. 

MELANOLITE  :  Na2O,  FeO,  A12O3,  Fe203,  SiO2,  EUO  (about  10  per 
cent.).  In  black,  sub-fibrous  coatings  of  waxy  lustre  and  somewhat 
greasy  feel ;  H  1'5-2'0 ;  G  2'7-2'9.  Easily  fusible  into  a  black  mag- 
netic globule. 

SELADONITE  (Green  Earth) :  K20,  MgO,  FeO,  A1O3,  SiOa,  H2O, 
mixed  with  CaOCO2,  <fcc.  In  earthy  or  compact  masses  and  coatings  in 
amygdaloidal  traps,  and  also  frequently  in  pseudomorphs  after  augite. 
Green  of  various  shades ;  somewhat  shining  in  the  streak ;  H  1  -0-2-0 ; 


MINERAL   TABLES  : — XXVII.  259 

O  2-8-2*9.  BB,  melt's  into  a  black  magnetic  bead.  In  hydrochloric 
acid  loses  its  colour,  and  is  slowly  decomposed  with  separation  of 
fine-granular  silica.  Glauconite  or  Green-Sand,  in  disseminated  par- 
ticles and  grains  in  cretaceous  and  other  strata,  is  of  generally  similar 
character.  Both  substances,  when  ignited  in  the  Bunsen-flame,  shew 
the  red  K-line,  in  the  spectroscope,  very  distinctly. 

A3. -INSOLUBLE  IN  HYDROCHLORIC  ACID,  OR  SCARCELY  ATTACKED  BY 
THAT   REAGENT. 

f  In  masses  or  crystals  of  leafy  or  scaly  structure  with  strongly-marked 

cleavage  in  one  direction. 

(Fusible  in  thin  pieces}. 

FERRUGINOUS  MICAS  (BIOTITE,  &c.) :  Yield  traces  of  water  in  some 
examples,  only;  as  a  rule,  fuse  merely  on  the  edges.  See  TABLE  XXY. 

(More  or  less  brittle.  Hardness  insufficient  to  scratch  glass). 
STILPNOMELANE  :  Essential  components — MgO,  FeO,  A12O3,  SiO*, 
H20  (about  9  pfer  cent.).  In  dark-green  or  greenish-black  radio- 
foliated  masses  or  small  scaly  particles.  H  3-0-3-5  j  G  2-8-3-4. 
Fusible  (in  some  cases  readily,  in  others  slowly)  into  a  magnetic  slag 
or  globule.  Scarcely  attacked  by  acids. 

(Hardness  sufficient  to  scratch  glass  slightly). 

CHLORITOID:  Average  composition — MgO  3-0,  FeO  27-0,  APO* 
39-0,  SiO2  26,  H20  7-0.  In  dark  or  blackish-green,  foliated  and 
scaly-granular  masses,  the  folise  more  or  less  curved  and  brittle. 
H  5-5 ;  G  3-5-3-6.  BB,  slowly  fusible  (often  on  the  edges  only) 
into  a  black  magnetic  slag.  Slightly  attacked  by  hydrochloric,  but 
readily  decomposed  by  sulphuric  acid.  Sismondine  (blackish-green), 
and  Masonite  (dark  greenish-grey)  are  apparently  identical.  Ottre- 
lite  (greenish -grey  to  greenish-black,  in  small  six-sided  tables  with 
rounded  angles,  in  certain  clay  slates)  is  also  closely  related.  It 
gives,  BB,  with  carb.  soda  a  strong  manganese-reaction. 

f  f  In  fibrous  masses. 

(Easily  fusible). 

KROKYDOLITE  (Crocidolite) :  Na2O,  MgO,  FeO,  SK>,  H20  (2:5 
to  5  per  cent.).  In  deep-blue  or  lavender-blue  fibrous  masses,  the 
fibres  tough  and  flexible.  H  3-0-4 -0 ;  G  3-2-3-3.  Easily  fusible  into 
a  black  magnetic  globule. 


260  BLOWPIPE  PRACTICE. 


KIRWANITE;  CaO,  FeO,  APO3,  SiO2,  HzO  (about  4  per  cent.). 
In  opaque  dark-green  nodular  masses  of  radiated-fibrous  structure. 
H  2-0  ;  G  2-9.  BB  black  ens-,  and  melts. 

(Fusible  on  edges  only.) 

XYLITE  :  CaO,  MgO,  Fe203,  SiO2,  H20  (47  per  cent.),  with  small 
(accidental  V)  amount  of  CuO.  In  opaque  nut-brown,  fibrous  or 
ligniform  masses.  H  3'0  ;  G  2-93.  Fusible  on  the  edges  only.  Dis- 
tinguished from  Xylotile  or  Mountain  Wood,  proper,  by  its  resist- 
ance to  acids.  It  differs  also  from  the  latter  mineral  by  containing 
(according  to  Hermann's  analysis)  a  certain  amount  of  lime. 

Iff  In  more  or  less  earthy  or  compact  masses. 
.  SORDAWALITE  :  MgO,  FeO  (or  Fe203),  APO3,  SiO2,  H20,  with  inter- 
mixed ferrous  phosphate,  &c.  In  black  or  dark-green  coatings  and 
earthy  masses,  weathering  brown.  H  4*0-4-5  (?);  G  2-6;  fusible 
into  a  black  magnetic  globule.  Partially  decomposed  by  hydro- 
chloric acid.  Hitherto,  from  Finland  only. 

CHLOROPHJSITE  :  MgO,  FeO,  SiO2,  H2O  (about  42  per  cent.).  In 
green  or  brownish-green  amygdaloidal  masses  in  trappean  rocks. 
Weathers  brown  and  black.  H  l'O-2'O;  G  about  2-0.  BB,  forms 
a  black  magnetic  slag  or  globule.  Distinguished  from  Delessite, 
Lillite,  Chamoisite,  &c.,  by  its  resistance  to  hydrochloric  acid,  and 
by  the  large  amount  of  water  which  it  yields  on  ignition.  Nigrescite, 
a  green  amygdaloidal  mineral,  blackening  on  exposure,  is  identical 
or  closely  related. 

B.  —  Fusion-product,  non-magnetic. 

BV—  FUSIBLE  ON  THE  EDGES  OR  IN  FINE  SCALES  OR  SPLINTERS  ONLY;  BUT 
EXFOLIATING  AND  CURLING  UP,  IN  SOME  CASES,  ON  IGNITION. 

f  Micaceous  or  scaly  minerals. 

(  Water  under  5  '5  per  cent.     In  bulb-tube  little  more  than  traces  evolved.  ) 
MUSCOVITE  (Ordinary  or  Potash  Mica):  Elastic  in  thin  leaves. 
Not  decomposed  by  sulphuric  acid.     See  TABLE  XXV.,  page  213. 

DAMOURITE  :  KX)  11-20,  APO3  37'85,  SiO2  45-22,  H2O  5-25.  In 
yellowish-white  pearly  scales  and  foliated  masses,  associated  (as 
regards  known  localities)  with  Staurolite  and  Cyanite,  or  with 
Corundum.  H  1-5-2-5;  G  2-8.  BB  exfoliates,  and  melts  on  edges. 
Decomposed,  with  separation  of  silica  scales,  by  sulphuric  acid. 


MINERAL  TABLES: — xxvii.  261 

Margarodite  and  Sericite  are  closely  allied  micaceous  substances,  ap- 
parently altered  Muscovite,  with  variable  amounts  of  water.  All 
shew  the  red  K-line  in  the  spectroscope  very  distinctly. 

PARAGONITE  (Hydrous  Soda-Mica):  NaK),  K2O,  A12O*,  SiO2,  H'O 
(2 -5  to  4'5  per  cent.).  In  scaly  or  schistose  masses  of  a  yellowish- 
white,  pale-grey,  or  light-green  colour,  and  pearly  lustre,  H  2-0- 
3'0;  G  2 -7 9.  Fusible  on  the  edges  into  a  white  enamel;  decom- 
posed by  sulphuric  acid.  Pregrattite,  distinguished  by  marked  ex- 
foliation BB,  is  closely  related, 

OELLACHERITE  (Hydrous  Barium-Mica) :  K20,  Na20,  SrO,  BaO, 
CaO,  MgO,  APO,  SiO2,  H2O  (about  4  or  4'5  per  cent.).  In  white  or 
pale-green  scaly  masses  of  pearly  lustre,  H  1'5-3*0  (?);  G  2-8  2 '9. 
Fusible  into  a  white  enamel.  Should  be  readily  distinguished  by  its 
spectroscopic  reactions,  but  the  author  has  not  been  able  to  procure 
a  specimen  for  examination, 

PHLOGOPITE  (Potassic-Magnesian  Mica)  :  In  golden-brown,  mica- 
ceous crystals  and  masses.  Decomposed  by  sulphuric  acid.  See 
TABLE  XXV.,  page  213. 

COOKEITE  :  A  hydrous  mica,  giving  marked  lithium  reaction  BB, 
or  in  spectroscope.  Forms  red  or  reddish-grey  scaly  aggregations. 
Probably  altered  Lepidolite. 

RUBELLANE  :  Na*O,  K*O,  MgO,  Fe203,  A12O3,  SiO2,  H20.  In  red 
or  brownish-red  hexagonal  tables  with  pearly  lustre  on  cleavage 
plane.  H  about  2-5 ;  somewhat  brittle.  BB,  melts  (in  some  cases 
on  edges  only)  into  a  dark  ferruginous  glass.  Regarded  as  an  altered 
Mica.  Occurs  in  certain  trachytes  and  other  volcanic  rocks.  Hel- 
vetane  (copper-red,  yellow,  green)  is  closely  related. 

MABGARITE  (Pearl  Mica)  :  In  white  or  light-coloured  scaly  and 
foliated  masses  with  strong  pearly  lustre.  Fusible  on  edges,  only, 
but  in  some  cases  with  slight  bubbling.  Moistened  with  hydro- 
chloric acid,  shews  momentary  red  and  green  Ca-lines  in  spectroscope. 
See  TABLE  XXV.,  page  215. 

TALC  :  MgO,  SiO2,  with  small  amount  of  basic  water.  In  white, 
light-green  or  other  foliated  or  scaly  examples,  with  pearly  lustre. 
H  1  '0  ;  very  sectile,  flexible,  and  soapy  to  the  touch.  BB,  exfoliates, 
but  melts  on  thin  edges  only.  Evolves  merely  traces  of  water  in  the 
bulb-tube.  With  Co-solution  becomes  flesh-red.  See  TABLE 
page  214. 


262  BLOWPIPE    PRACTICE. 

(Water,  5 '6  to  14  per  cent. :  evolved  in  marked  quantity  in  bulb-tube.) 
PYROPHYLLITE  :  APO3,  SiO2,  IPO,  with  traces  of  MgO,  &c.  In 
light-green  or  greenish- white  radio-foliated  and  scaly  masses.  H  1  *0. 
BB,  exfoliates  and  curls  up,  but  remains  practically  unfused.  Be- 
comes blue  by  ignition  with  Co-solution.  Belongs  properly  to  Table 
XXV.:  see  page  214.  See  also  Nacrite  or  Pholerite,  page  219. 

YERMICULITE  :  MgO,  FeO,  APO3,  SiO2,  H2O,  with  traces  of  CaO, 
K20,  &c.  In  scaly  and  coarsely-foliated  examples  and  six-sided 
micaceous  tables  of  a  yellowish -brown,  yellow  or  green  colour.  HI  -0- 
1-5;  G  2-2-2-4;  slightly  flexible  in  thin  leaves.  BB,  expands  and 
curls  up  greatly,  and  melts  subsequently  to  a  white  or  greyish  en- 
amel. According  to  Prof.  Cooke,  should  form  three  species  :  Jef- 
ferisite,  Culsageeite,  Hallite. 

CHLORITE  (Pennine);  and  RIPIDOLITE  or  CLINOCHLORE  :  In  green, 
scaly  or  foliated  masses  and  micaceous  crystals.  As  a  rule,  fusible 
on  the  edges  only,  in  many  cases  into  a  black,  slightly  magnetic  en- 
amel. Belong  properly  to  Table  XXY. :  see  page  213. 

f  f  Minerals  of  compact,  fibrous,  or  other  non-micaceous  structure. 
More  or  less  distinctly  sectile* 

(Assume  a  blue  colour  after  ignition  with  Co-solution.) 

AGALMATOLITE  :  Massive,  fine-granular,  or  compact  in  structure ; 
white,  greyish,  greenish,  &c.  The  substance  of  many  Chinese  "  Figure- 
stones."  Fusible  on  thin  edges,  only.  See  page  219,  TABLE  XXY. 

PINITE,  FAHLUNITE,  PYRARGILLITE  ;  WEISSITE  ;  IBERITE  ;  ESMARK- 
ITE;  BONSDORFFITE  :  In  more  or  less  dull  and  opaque  crystals — 
essentially  six-sided,  eight-sided  or  twelve-sided  prisms — of  a  greyish- 
white,  grey,  brown,  green  or  dull-bluish  colour.  Fusible  on  the  edges 
only.  See  page  220,  TABLE  XXY. 

KILLINITE  :  K20,  FeO,  APO3,  SiO2,  H'O  (about  9  or  10  per  cent., 
or  less  in  some  cases).  '  Chiefly  in  greenish-grey  or  brownish-yellow 
columnar  or  broad-prismatic  aggregations,  translucent  in  thin  pieces. 
H  3-0-4-0;  G  about  2-7.  BB,  expands  somewhat,  and  melts  slowly 
(in  some  cases  on  the  edges  and  surface  only)  into  a  white  or  greyish 
enamel.  Decomposed,  in  powder,  by  sulphuric  acid. 

SCHR^ETTERITE  (Hydrargillite  (?)  mixed  with  a  lime  or  other  sili- 

*  The  minerals  of  this  section  are  fusible,  as  a  rule,  upon  the  edges  only.    They  belong  pro- 
perly, therefore,  to  TABLE  XXV.     See  pages  219-222. 


MINERAL  TABLES  : XXVII.  263 

cate,  traces  of  copper  sulphate,  &c.  Yields  on  ignition  from  36  to 
41  per  cent,  water).  In  earthy  and  botryoidal  masses,  coatings,  &c., 
of  a  green,  pale-yellow,  grey,  or  brownish  colour,  with  more  or  less 
conchoidal  fracture.  H  3'0-4'0  ;  G  about  2.  BB,  whitens,  and 
fuses  slowly  (often  on  edges  only)  into  a  white  or  light-grey  enamel- 
Decomposed  (with  gelatinization,  according  to  .Fischer)  by  hydro- 
chloric acid, 

PYKNOTROPE  :  K20,  MgO,  APOS,  SiO*,  H20  (about  7  or  8  per 
cent.).    In  greyish- white,  pale-greenish,  or  brownish-red,  coarse-gram 
lar  masses,  with  cleavage  in  two  directions  at  right-angles.     H  2'0- 
3-0  ;  G  2-6-2-72.     BB,  fusible  only  in  thin  splinters  or  on  the  edges. 
Associated  with  serpentine. 

(Assume  a  flesh-red  colour  by  ignition  with  Co-solution,  or  do  not,  othervnty* 

become  blue).*  *%  ftf* 

STEATITE  (Compact  or  Granular  Talc):   In  masses  and  pseudb-^ 
morphous  crystals  of  a  white,  grey,  greenish  or  other  colour,  often 
mottled.     Yery  sectile ;   yields  very  little  water  in  bulb-tube,  but 
blackens  more  or  less.     BB,  hardens,  and  fuses  on  thin  edges.     See 
page  222. 

SERPENTINE  :  Forms  compact,  fine-granular,  or  other  masses,  of  a 
green,  red-brown,  yellowish-grey,  or  variegated  colour.  In  bulb-tube, 
yields  about  12  or  13  per  cent,  water.  Fusible  on  thin  edges  Only. 
See  page  221,  TABLE  XXV. 

ORYSOLITE  (Fibrous  Serpentine) :  In  silky,  parallel-fibrous  masses 
of  a  yellowish-white  or  green  colour,  the  fibres  easily  separable. 
Melts  at  the  point  of  a  fine  fibre  into  a  white  or  greyish  enamel.  See 
page  221,  TABLE  XXV. 

MEERSCHAUM  (Sepiolite) :  In  fine-granular  or  compact  masses  of  a 
white  or  pale  yellowish  colour,  adherent  to  the  tongue.  BB,  hardens, 
but  fuses  on  thin  edges  only.  See  page  221,  TABLE  XXV. 

t  Not  sectile.     Hardness  sufficient  to  scratch  glass. 
POLLUX  :    In  translucent,  camphor-like  masses  and  small  crystals 
(combinations  of  cube  and  trapezohedron  2-2).     Yields  traces  only 
of  water  in  bulb-tube,  and  fuses  only,  BB,  on  thinnest  edges.     See 
page  203,  TABLE  XXIV. 

*  In  the  bulb-tube,  all  blacken  on  evolving  water. 


264  BLOWPIPE    PRACTICE. 

B«. -FUSIBLE  WITHOUT  MARKED  BUBBLING  OR  PREVIOUS  INTUMESCENCE. 

f  Insoluble  in  hydrochloric  acid. 

DIALLAGE  (Schistose  and  more  or  less  altered  Pyroxene) :  In  foliated 
or  sub-foliated  masses  of  a  greyish-green  or  greenish-brown  colour  and 
metallic  pearly  lustre.  Yields  often  merely  traces  of  water  :  in  no 
case  more  than  3  or  4  per  cent.  See  page  242,  TABLE  XXVI. 

t-t  Decomposed,  by  hydrochloric  acid,  with  production  of  chlorine  fumes. 
(BB,  with  carb.  soda,  strong  Mn-reaction.) 

KCIPSTEINITE  :  MgO,  MnO,  Mn2O3,  Fe2Os,  SiO2,  H20  (9  per  cent.). 
In  amorphous  masses  of  a  brown  or  brownish-grey  colour,  with 
reddish-brown  streak;  H  5*0  j  G  3-5.  Fusible  into  a  dark  slag. 

t  f  t  Decomposed,  with  or  without  gelatinization,  by  hydrochloric  acid. 
(BB,  with  borax,  a  chrome-green  glass. ) 

PYROSCLERITE  :  MgO,  FeO,  APO3,  (VO3  (1-43  per  cent.),  SiO2, 
H2O  (11  per  cent.),  von  Kobell.  In  cleavable  masses,  indicating 
Rhombic  crystallization  ;  in  thin  pieces  somewhat  flexible  ;  H  3'0  ; 
G  2 '7-2 -8;  green  of  various  shades,  with  pearly  lustre  on  cleavage- 
planes.  Fusible  quietly^  or  with  slight  bubbling  only,  into  a  greenish- 
grey  enamel.  Hitherto,  from  Elba  only. 

(In  spectroscope,  marked  Ba-reaction  when  moistened  with  hydrochloric  acid.) 
HARMOTOME:  K2O  3*3,  BaO  20,  A12O8  15-7,  SiO2  46,  H2O  15. 
Rhombic  (?) :  commonly  in  groups  of  small,  cruciform  crystals,  with 
calcite,  &c.,  in  trap  amygdaloids.  Generally  colourless,  otherwise 
white,  grey,  reddish,  brown,  &c<;  H  4'5  -;  G  2 -4-2 -5.  Fuses  quietly, 
with  pale-green  coloration  of  the  flame-border.  Decomposed  by 
hydrochloric  acid,  with  separation  of  fine-granular  silica.  See  Note 
at  end  of  Table. 

EDINGTONITE  :  BaO  26-84,  A12O8  22-63,  SiO2  36-98,  H2O  12-46, 
Heddle,  Tetragonal;  crystals,  mostly,  small  square  prisms  with 
hemihedral  polar  planes;  greyish-white,  pale-red;  H  4-0-4-5  ;  G  2 -7. 
Gelatinizes  in  hydrochloric  acid.  Hitherto,  from  Scotland  only',' 
accompanying  harmotome,  analcime,  calcite,  &c. 


MINERAL   TABLES  :— XXVII.  265 

(In  spectroscope,  marked  Ca-reaction  when  moistened,  after  ignition,  with  hydro- 
chloric acid.*) 

PECTOLITE  :  Na2O,  CaO,  APO3,  SiO2,  H2O.  Clino-Rh.  ;  but  com- 
monly in  cleavable  fibrous  or  sub-fibrous  masses,  with  cleavage  angle 

of  95°  23'  (  =  B  :  Y).  Colourless,  or  greyish  or  pale  greenish- white, 
often  opaque  and  more  or  less  earthy  from  alteration.  H  (in  un- 
weathered  examples)  5-0;  G- 2-74-2-88.  Fuses  quietly.  Yields  as  a 
I'ule  only  2  or  3  per  cent,  water  on  ignition.  Decomposed  without 
gelatinization  by  hydrochloric  acid,  but  gelatinizes  after  fusion. 

CHALILITE:  Na2O,  CaO,  MgO,  APO3,  Fe2O3,  SiO*,  H*O  (about  16 
per  cent.).  Reddish -brown,  massive;  H  4-5 ;  G  2*25.  An  imperfectly- 
known  mineral,  hitherto  from  Antrim  only. 

ANALCIME  ;  NATROLITE  :  Normally  lime  free,  but  some  examples 
of  exceptional  occurrence  shew  momentary  Ca-lines  in  spectroscope, 
see  below. 

(In  spectroscope,  no  Co-lines,  but  strong  Na-reaction.) 

ANALCIME:  Na20  14-0,  APO*  23-3,  SiO2  54-5,  H2O  8-2;  but  a 
small  percentage  of  CaO  present  in  some  varieties  and  K2O  in  others. 
Regular ;  crystals  either  small  cubes  with  angles  replaced  by  the  planes 
of  the  trapezohedron  2-2,  or  the  latter  form  alone.  Colourless,  white, 
light-grey,  flesh-red ;  H  5*5 ;  G  2-1-1 -3.  Fusible  without  intumescence 
into  a  more  or  less  clear  glass.  Decomposed  by  hydrochloric  acid  with 
separation  of  slimy  silica.  See  Note  at  end  of  Table.  Cuboite  is  a 
green  or  greenish -grey  variety.  Eudn  ophite  is  regarded  as  a  Rhombic 
Analcime.  Cluthalite  is  a  somewhat  decomposed  variety. 

NATROLITE  (Mesotype  in  part)  :  Na*O  16-30,  APO3  26-96,  SiO* 
47-29,  H2O  9-45,  but  traces  of  CaO,  &c.,  occasionally  present. 
Rhombic  ;  crystals  very  small,  often  acicular  ;  essentially  Rhombic 
(almost  rectangular)  prisms,  terminated  by  the  planes  of  a  rhombic 
octahedron.  Y:  Y  91°;  P:  P,  over  polar  edges,  143°  20'aiidl42°  40'. 
Occurs  also,  and  more  commonly,  in  radio-fibrous  masses,  often  with 
crystalline  botryoidal  surface.  Colourless,  white,  yellow,  light-brown, 

*  If  a  zeolitic  mineral  do  not  shew  these  spectroscopic  reactions  very  distinctly  when  simply 
moistened  by  hydrochloric  acid,  a  portion  m  fine  powder  should  be  dissolved  in  the  acid  m  a 
Binall  porcelain  capsule  with  attached  handle  (like  that  figured  on  page  20)  over  the  spirit-lamp 
or  Bunsen-flame.  A  drop  of  the  solution  may  then  be  takeh  up  by  a  platinum  wire  (bent  at  the 
extremity  into  a  small  loop  or  ear)  and  held  within  the  edge  of  the  flame,  care  being  taken  to 
test  the  wire  previously  for  negative  results.  By  this  treatment,  distinct  although  more  or  less 
transitory  spectra  are  always  obtained  when  lime,  baryta,  potash..  &c.,  are  present  in  the  mineral. 


266  BLOWPIPE    PRACTICE. 

red ;  two  or  more  tints  frequently  present  in  concentric  zones  in  the 
same  example.  H  5-0-5-5  ;  A  2-17-2-27.  Very  easily  fusible  in  the 
simple  candle  or  Bunsen-flame,  without  intumescence,  into  a  colourless 
glass.  Decomposed,  with  gelatinization,  by  hydrochloric  acid, 
Eadiolite  or  Bergemanite,  Lehuntite,  Galactite,  Brevicite,  Fargite, 
are  varieties.  Mesolite  (AntrimoKte,  Harringtonite)  is  a  closely 
related  zeolitic  mineral,  but  contains  both  lime  and  soda,  and  is  thus 
intermediate  between  Natrolite  and  Scolecite.  It  occurs  essentially  in 
radio-fibrous  masses  and  acicular  crystals.  Yields  12  to  14  percent, 
water ;  gelatinizes  in  hydrochloric  acid,  and  fuses  quietly  or  with  very 
slight  intumescence. 

B».-FUSIBLE  WITH  MUCH  BUBBLING  OR  WITH  PREVIOUS  INTUMESCENCE. 

T  Undissolved  or  scarcely  attacked  by  hydrochloric  acid. 
(In  yellow,  fibrous  examples.     BB,  strong  Mn-reaction.) 

CARPHOLITE  :  MnO,  FeO,  Fe2O3,  AFO3,  SiO2,  IPO  (10  to  11  per 
cent.),  with  small  amounts  of  MgO,  F,  &c.  Acicular,  or  in  radio- 
fibrous  aggregates  of  a  straw-yellow  or  greenish-yellow  colour  and 
silky  lustre;  H  4-5-5*0;  G  2-9-3-0.  The  water  evolved  by  strong 
ignition  deposits  spots  of  silica  on  the  sides  of  the  bulb-tube,  and 
attacks  the  glass.  BB,  intumesces  and  forms  a  dull-brownish  bead. 

(In  opaque,  prismatic  crystals. ) 

GIGANTOLITE  :  Na2O  1-2,  K2O  27,  MgO  3-8,  MnO  0-9,  A12O325-0, 
Fe2O3 15-6,  SiO2  46-3,  H2O,  6-0.  Rhombic  ;  crystals  (probably  pseudo- 
morphous  after  lolite),  thick,  twelve-sided  prisms,  more  or  less  dull ; 
green,  greenish-grey  ;  H  3'5  ;  G  2'8-2-9.  Fusible  with  bubblingjnto 
a  greenish  slag.  When  ignited  and  moistened  with  hydrochloric  acid, 
shews  red  K-line  distinctly  in  spectroscope. 

(In  pale-red  cleavable  masses.) 

WILSONITE  :  K2O,  CaO,  MnO,  FeO,  A12O3,  SiO2,  H2O.  In  rose-red 
or  pale  purplish-red  cleavable  masses ;  slightly  tibroi  s  and  pearly  in 
the  cleavage  directions,  lustreless  and  more  deeply-coloured  trans- 
versely;  cleavage  rectangular;  H  S'0-3'5  on  cleavage  surfaces,  other- 
wise 5'0-5'5  ;  G  275-2*8.  BB,  expands  or  increases  in  volume,  and 
fuses  with  slight  bubbling  into  a  very  blebby  glass  or  white  enamel. 


MINERAL   TABLES  I XXVII.  26Y 

Moistened  with  hydrochloric  acid,  shews  Ca-lines  in  flashes,  and  red 
K-line  persistently.* 

f  f  Decomposed  by  hydrochloric  acid,  with  separation  of  granular  or 

slimy  silica. 
(Hardness  6'0  or  7'0.     Scratch  glass  strongly.) 

PREHNITE:  CaO  27-14,  APOS  24-87,  SiO2  43-63,  IPO  4-36. 
Rhombic ;  crystals  tabular  or  short-prismatic,  in  aggregated  groups 
(see  Note  at  end  of  Table).  Occurs  also,  and  more  commonly,  in 
radio-fibrous  masses  with  botryoidal  and  crystalline  surface;  greenish- 
white  passing  into  distinct  shades  of  green;  H  6-0-7'Q;  G  2-8-3-0. 
Fusible  with  continued  bubbling.  In  spectroscope,  when  moistened 
with  hydrochloric  acid,  especially  after  fusion,  shews  red  and  green 
Ca-lines  in  flashes.  The  fused  bead  gelatinizes  in  the  acid,  but  in  its 
normal  state  Phrenite  is  more  or  less  slowly  and  incompletely  decom- 
posed, with  separation  of  fine  granular  silica.  Konpholite  is  a  thin 
tabular  variety,  which  blackens  on  ignition  from  the  presence  of 
intermixed  dust  or  organic  matter.  Chlorastrolite  from  Isle  Royale, 
Lake  Superior,  in  small  nodular  masses  of  green  colour  and  radio- 
fibrous  structure,  is  also  a  variety  or  related  substance,  intermixed 
with  grains  of  magnetic  iron  ore,  &c. 

FAUJASITE:  KX>  4-36,  Na2O  4-84,  CaO  4-36,  APOS  16-00,  SiO8 
46-77,  H2O  28-03.  Regular;  crystals,  small  octahedrons  (or  accord- 
ing to  Knop,  very  flat-planed  trapezohedrons),  sometimes  twinned  ; 
white  or  brownish  ;  H  6-0 ;  G  1-9-1-95.  BB,  intumesces,  and  fuses 
readily.  In  the  bulb-tube  yields  a  large  amount  of  water. 

(H  4-5  to  5'0.    No  essential  precipitate  formed  in  the  diluted  solution  on  addition 

of  ammonia. ) 

APOPHYLLITE  (Ichthyopthalmite)  :  CaO  24-72,  SiO8  52-97,  H2O 
15 '90,  KF  6-40.  Tetragonal ;  crystals  commonly  square  prisms  with 
truncated  angles,  or  acute  square-based  octahedrons,  mostly  with 
basal  plane  (see  Note  at  end  of  Table);  colourless,  pale-red,  brownish, 
&c.,  with  pearly  lustre  on  basal  plane,  the  latter  also  frequently 
iridescent;  H  4-5-5-0;  G  2'3-2'4.  BB,  exfoliates,  and  melts  with 

*  Whilst  this  mineral  has  much  the  composition  of  a  Finite,  its  general  aspect  ami  physical 
characters  are  very  different,  and  have  caused  it  to  be  regarded  as  an  altered  Scapolite.  The 
presence  of  potash  is  the  chief  object-ion  to  the  latter  view.  Were  it  not  for  its  sub-fibrous 
structure,  as  seen  on  the  cleavage  surface  more  especially,  it  might  be  considered  an  altered 
Oithoclase. 


268  BLOWPIPE    PEACTICE. 

bubbling  to  a  white  glass.  Gives  fluorine  reaction  with  fused 
phosphor-salt  in  open  tube  (page  26).  Moistened  with  hydrochloric 
acid,  shews  Ca-lines  in  flashes,  and  persistent  red  K-line.  Albin  is 
an  opaque-white,  slightly  weathered  variety.  Oxhaverite,  Tesselite, 
are  also  varieties. 

OKENITE  :  CaO  26-42,  SiO  56-60,  H?O  16-98.  Rhombic  in  crystal., 
but  chiefly  in  fibrous  masses,  more  or  less  tough;  colourless,  pale- 
bluish  or  yellowish- white ;  H  5  -0 ;  G  2-28-2-36.  Fusible  with  bubbling 
into  a  white  glass  or  enamel.  In  spectroscope,  no  red  K-line. 

PECTOLITE  :  See  under  B2,  above. 

(H  5*0  to  5'5.     A  marked  precipitate  [insol.  in  acids]  formed  in  the  diluted 
solution  by  sulphuric  acid.) 

BREWSTERITE  :  BaO,  SrO,  APO,  SiO2,  H2O  (13-6  per  cent.),  with 
traces  of  CaO,  &c.  Clino-Rh.;  crystals,  small,  vertically -striated 
prisms,  terminated  by  the  two  planes  of  a  very  flat  side-polar  or  clino- 

dome;  Y:Y  136°;  P  on  P  over  summit  172°.  Yellowish-white, 
pale-brown;  H  5'0-5'5  ;  G  2-2-2-45.  Fusible  with  intumescence  and 
bubbling.  Moistened  with  hydrochloric  acid,  shews  in  spectroscope 
transitory  Ba  and  Sr  lines  (see  page  56),  but  in  some  examples  the 
reaction  is  not  very  strongly  marked. 

(H  4'5  or  less.     Crystalline  and  cleavable.    A  copious  precipitate  in  diluted  solu- 
tion thrown  doivn  on  addition  of  ammonia.) 

CHABASITE:  Average  composition:  K2O  T98,  CaO  9-43,  A12O» 
17-26,  SiO2  50-50,  H'O  20-83.  Hemi- Hexagonal ;  crystals,  commonly 
small  rhombohedrons,  often  twinned,  the  twin-axis  corresponding 
with  the  vertical  axis  ;  R :  R  94°-95°,  commonly  94°  46'  (see  Note  at 
end  of  Table);  colourless,  white,  pale-red,  &c. ;  lustre,  vitreous;  H 
4'0-4'5  ;  G  2 '0-2 -2.  BB  intumesces  and  fuses  into  a  very  blebby 
glass  or  white  enamel.  Decomposed  by  hydrochloric  acid,  with 
separation  of  slimy  silica.  In  spectroscope,  the  solution,  or  a  splinter 
moistened  with  the  acid,  shews  red  and  green  Ca-lines  in  flashes,  with 
feeble  and  very  transitory  display  of  the  red  K-line.  Acadialite  is  a 
reddish  Chabasite  from  Nova  Scotia.  Phacolite  is  a  variety  in  inter- 
penetrating very  obtuse  twelve-sided  pyramids  (with  other  accom- 
panying forms),  often  lenticular  from  distortion.  Haydenite  and 
Seebachite  are  also  varieties.  Levyne  and  Herschellite  are  closely 


MINERAL  TABLES: — xxvn.  ?69 

related  compounds,  occurring  mostly  in  hexagonal  or  pseudo-hexagonal 
tabular  crystals  with  large  basal  plane.  Gmelinite  is  also  very 
similar,  but  gelatinizes  in  hydrochloric  acid  :  see  below,  page  271. 

STILBITE  (Desmine  of  German  systems) :  CaO  9,  APO3  1 6,  SiO2  f>?, 
IPO  17,  with,  occasionally,  traces  of  Na2O  and  K2O.  Rhombic; 
crystals  small  and  commonly  in  groups,  consisting  usually  of  a 

rectangular  prism  ( =  V,  Y,  the  V  planes  vertically  striated),  ter- 
minated by  a  rhombic  octahedron  P,  the  latter  measuring  119°  16' 
and  114°  over  polar  edges,  and  occasionally  having  its  apex  truncated 
by  a  small  basal  plane.  Cleavage  very  perfect  parallel  to  the  side 

vertical  or  brachypinakoid  V,  the  cleavage-lustre  strongly  pearly. 
Occurs  also  abundantly  in  radio-fibrous  and  leafy  aggregations. 
Colourless,  white,  red,  brown,  <fec.;  H  3-5-4-0;  G-  2-1-2-2.  BB, 
intumesces,  and  fuses  into  a  very  blebby  glass.  Decomposed  by 
hydrochloric  acid,  with  deposition  of  slimy  silica.  Epistilbite  agrees 
in  composition  and  general  characters,  but  its  crystals  are  small 

rhombic  prisms  terminated  by  the  front  and  side  polars  P  and  P,  the 
latter  predominating.  Y:Y  135°  10';  P:P~over  summit  109°  46', 

P:P147°40'.  Colourless  or  bluish- white.  In  hydrochloric  acid, 
decomposed  with  separation  of  fine  granular  silica. 

HEULANDITE  (Stilbite  of  most  German  systems):  CaO  (with  small 
amount  of  Na2O  and  K2O)  9-34,  APO3  16-83,  SiO2  59-06,  HX)  14-77. 
Clino-R-hombic ;  crystals  mostly  tabular  parallel  to  the  side  or  clino- 
vertical  plane ;  commonly  made  up  of  the  front  and  side  verticals 

Y  and  Y  (the  latter  predominating)  with  a  front  polar  P,  and  narrow 

Base.  When  lying  consequently  with  Y  upwards,  the  crystals 
present  a  pseudo-hexagonal  aspect.  P:  Y  129°  40';  B:  Y  116°  20' 

and  63°  40'.  Cleavage  very  perfect  parallel  to  A7,  the  planes,  as  in 
Stilbite,  strongly  pearly.  Colour,  hardness,  and  other  characters, 
physical  and  chemical,  like  those  of  Stilbite.  Euzeolite,  Lincolnite, 
Beaumontite  (?)  are  varieties. 

(In  amorphous  examples  without  distinct  cleavage. ) 

CHONIKRITE:  CaO,  MgO,  APO3,  SiO2,  IPO  (9  per  cent.).  In 
snow-white  or  pale-yellowish,  disseminated  masses;  H  2-5-3,  more 
or  less  sectile ;  G  2-9.  BB,  fusible  with  bubbling  into  a  greyish- 


270  BLOWPIPE    PRACTICE. 

white  glass  or  enamel.  Decomposed  by  hydrochloric  acid,  with 
separation  of  granular  silica.  Hitherto,  from  Elba  only.  Related 
to  Pyrosclerite,  page  265  above. 

Iff  Decomposed,  with  perfect  gelatinization,  ly  hydrochloric  acid. 

'   (BB,  sulphur-reaction  with  carb.  soda.) 

ITTNERITE  :  K2O,  Na2O,  CaO,  AW3,  SiO2,  H20  (9-8  per  cent.)  In 
small,  granular  masses,  with  dodecahedral  cleavage,  of  a  grey  or  blue- 
grey  colour.  H  5-0-5-5  :  G  2-3-2-4.  Fusible  with  strong  bubbling 
into  a  blebby  semi-opaque  glass  or  enamel.  Yields  gypsum  to  boiling 
water,  as  recognized  by  the  precipitates  formed  in  the  solution  by 
oxalate  of  ammonia  and  chloride  of  barium,  respectively  (Fischer). 
Decomposed  by  hydrochloric  acid,  with  emission  of  sulphuretted 
hydrogen  and  separation  of  gelatinous  silica.  An  altered  Hauyne  or 
Nosean,  see  page  236. 

(BB,  flame-border  coloured  distinctly  green.) 

DATOLITE:  CaO  35-0,  B2O3  21-9,  SiO2  37'5,  H20  5-6.  Clino- 
Rhombic  (or  Ortho-Rhombic  T) ;  occurs  commonly  in  groups  of  small 
vitreous  crystals,  rich  in  planes  (see  Note  at  end  of  Table),  or  in 
coarsely  granular  masses.  Greenish-white,  colourless,  green,  reddish- 
white.  H  5-0-5-5  ;  G  2-8-3-0.  Fuses  very  easily,  with  much  bubbling, 
and  green  coloration  of  the  flame,  to  a  colourless  or  very  lightly- 
tinted  glass.  Gelatinizes  in  hydrochloric  acid.  In  spectroscope, 
shews  per  se  two  vivid  green  lines  with  one  pale-green  and  a  faint 
blue  line,  from  presence  of  B203.  When  moistened  with  hydrochloric 
acid,  a  test-fragment  shews  also  red  and  green  Ca-lines  in  flashes ;  but 
the  presence  of  lime  is  best  shewn  by  a  drop  of  the  solution,  taken 
up  in  a  double-loop  of  clean  platinum  wire  and  held  against  the  edge 
of  the  Bunsen-flame.  Humboldtite  is  a  variety  in  small  crystals, 
associated  with  lamellar  Apophyllite,  from  the  Tyrol. 

BOTRYOLITE  :  Contains  10*64  per  cent,  water,  and  occurs  in  fibro- 
botryoidal  examples  of  a  greenish,  pale-grey,  or  reddish  colour; 
otherwise  like  Datolite. 

(Moistened  with  hydrochloric  acid,  shew  distinct  red  K-line  in  spectroscope.) 
PHiLLiPSiTE(Lime-Harmotome,  Christianite) :  Average  composition, 
K20  7,  CaO  6,  A12O3  21-5,  SiO2  48-5,  H2O  17.     Rhombic  (?);  com- 
monly in  cruciform  crystals   resembling  those   of  Harmotome  (see 


MINERAL    TABLES  : XXVII.  271 

Note  at  end  of  Table).  Colourless,  white,  reddish-white,  pale-grey, 
&c.;  H  4-5-5-0  ;  G  2-15-2-2.  Fusible  with  intumescence  and  bubbling. 
Gelatinizes  in  hydrochloric  acid.  The  moistened  test,  or  the  solution, 
shews  K  and  Ca-lines  in  spectroscope,  the  latter  in  flashes  only. 

GISMONDINE  :  K20  2-85,  CaO  13-12,  AFO  27-33,  SiO2  35-88,  H2O 
21-10.  Tetragonal  (or  Rhombic?);  crystals  small,  and  often  imper- 
fectly formed  or  sub-spherical,  consisting  commonly  of  a  simple  pyramid 
or  octahedron  (with  angle  of  118°  30'  over  polar  edge,  and  92°  J$0' 
over  middle  edge),  or  of  this  form  combined  with  the  prism  V; 
greyish  or  reddish- white ;  H  5*0-6-0;  G  2-27.  Fusible  with  intu- 
mescence. See  Zeagonite,  below. 

ZEAGONITE:  K20  11-09,  CaO  5-31,  APO3  23*34,  SiO2  43-95,  H20 
15*31.  Rhombic;  crystals  mostly,  rectangular  prisms  (composed  of 

V  and  V)  with  angles  replaced  by  a  rhombic  octahedron  P,  measuring 
121°  44'  and  120°  37'  over  polar  edges,  and  89°  13'  over  middle 
edges,  the  planes  often  rounded  and  the  crystals  in  sub-spherical  groups. 
Colourless,  white,  pale-bluish ;  H  5*0-6-5  or  7,  the  latter  at  the  points 
and  edges.  Fusible  with  intumescence.  Probably  identical  with 
Gismondine,  both  being  Rhombic,  with  pseudo-tetragonal  aspect.  In 
spectroscope,  the  red  K-line  comes  out  very  distinctly. 

GMELINITE  ;  THOMSONITE  :  Shew  sometimes  in  spectroscope  a  feeble 
or  indistinct  K-line  :  see  below. 

HYDROTACHYLITE  :  In  -vitreous,  amorphous  masses  :  see  below, 
page  273. 

(No  distinct  K-line  brought  out  in  spectroscope). 

GMELINITE  :  Average  composition — Na20  (with  small  amount  of 
K20)  5,  CaO  5;  A12O3  20,  SiO2  48,  H20  21.  Hexagonal  or  Hemi- 
Hex.  ;  crystals,  commonly,  very  short  six-sided  prisms  (horizontally 
striated),  combined  with  a  six-sided  pyramid  measuring  142°  33'  over 
polar  edges,  and  79°  54'  over  middle  edges;  but  the  planes  of  the 
latter  often  alternate  in  size,  and  hence  the  pyramid  is  regarded  as 
consisting  of  two  complementary  rhombohedrons,  with  R  :  R  =  1 1 2° 
26'.  Colourless,  greenish-white,  yellowish-white,  pale-red.  H  4*5  ; 
G  2*0-2*1.  Fusible  with  intumescence.  Is  closely  allied  to  Chaba- 
site,  but  is  distinguished  by  the  presence  of  Na2O,  and  by  its  perfect 
gelatinization  in  hydrochloric  acid.  Ledererite  is  a  variety. 

THOMSONITE  (Comptonite) :  Ka2O  (with  small  amount  of  K2O,  4*4, 
CaO  13-3,  A1203  30*6,  SiO2  38*7',  IPO  43.  Rhombic  in  crystallize. 


272    .  BLOWPIPE    PRACTICE. 

tion,  but  cr}Tstals  usually  small  or  acicular  (see  note  at  end  of  Table), 

essentially  eight-sided  prisms  composed  of  the  forms  V,  Y,  and  V, 
with  V  planes  vertically  striated  (V:V  90C  40').  Occurs  chiefly  in 
fibrous  and  fibre-spherical  masses.  Colourless,  white,  reddish-white, 
brown.  H  5'0-5'5  ;  G  2-35-24.  Fusible  with  intumescence.  Gela- 
tinizes in  hydrochloric  acid.  In  spectroscope  the  solution  or  mois- 
tened fragment  shews  red  and  green  Ca-lines.  Ozarkite,  according  to 
Dana,  is  a  massive  Thomsonite.  Faroelite,  Scoulerite,  Chalilite,  are 
also  varieties ;  the  latter  red-brown,  and  partially  altered. 

SCOLECITE  (Mesotype  in  part):  CaO  14-26,  APO3  26-13,  SiO' 
45*85,  H20  13-76.  Clino-Rhombic ;  crystals  mostly  rhombic  prisms 
(with  Y  :  V  91°  35')  with  low  pyramidal  terminations  (P  and  -  P'), 
hence  much  resembling  an  ortho-rhombic  combination.  In.  general, 
however,  crysts.  very  small  or  acicular.  Occurs  commonly  in  fibrous 
and  radio-spherical  examples.  Colourless,  white,  reddish-white,  <fec.  H 
5-0-5-5  ;  G  2-2-2-4.  Fusible  with  intumescence,  the  more  typical 
examples  curling  up  greatly.  Acid  and  spectroscope  reactions  like 
those  of  Thomsonite.  Poonahlite  is  a  variety.  Mesolite  is  also  closely 
related,  but  contains  both  soda  and  lime,  and  fuses  more  or  less 
quietly.  See  under  Natrolite,  page  266. 

LAMONTITE:  CaO  12,  APO3  22,  SiO?  50,  H20  16;  but  the  latter 
usually  less,  from  the  ready  efflorescence  of  the  mineral.  Clino- 
Rhombic ;  crystals  essentially  rhombic  prisms,  with  Y  :  Y  (in  front) 
=  86°  16',  terminated  by  a  very  oblique  front-polar  or  hemi-ortho- 
dome*  inclined  on  the  Y  planes  at  angle  of  1 1 3°  30'.  Cleavage  very 
perfect  parallel  to  Y.  Occurs  also  very  commonly  in  columnar, 
fibrous,  and  sub-earthy  masses.  White,  yellowish  or  reddish-white, 
pale-red,  pale- grey.  H  3-5-4-0  normally,  but  often  less  from  partial 
disintegration.  G  2-25-2'36.  Fusible  with  intumescence  into  a  white 
enamel  or  very  blebby  glass.  Gelatinizes  in  hydrochloric  acid.  A 
drop  of  the  solution  on  loop  of  platinum  wire,  or  a  moistened  frag- 
ment of  the  mineral,  shews  in  spectroscope  red  and  green  Ca-lines. 
Leonhardite,  Caporcianite,  and  ^Edelforsite,t  are  identical  or  closely 
related. 

*  The  Basal  plane  of  French  crystallographers. 

t  This  is  the  so-called  "  Red  Zeolite  of  ^Edelfors."  Its  hardness  is  usually  stated  in  text- 
books to  equal  6'0,  an  error  arising  from  a  confusion  of  names —the  degree  of  hardness  in  ques- 
tion applying  to  an  older  "^Edelforsite,"  since  shewn  to  be  an  impure  Wollastonite  containing 
intermixed  quartz. 


MINERAL  TABLES  :— XXVII.  273 

(In  vitreous,  amorphous  masses). 

HYDROTACHYLITE  :  K2O,  Na20,  CaO,  MgO,  FeO,  Fe203,  APOS, 
TiO2,  SiO2,  H2O  (12-90  per  cent.),  according  to  Peterson  and  Senfter. 
Forms  nodular  and  other  masses  of  uncrystalline  structure  in  basalt. 
Dark-green  or  black.  H  3'5;  G  2'13.  Fusible  with  more  or  less 
bubbling.  Decomposed,  with  gelatinization,  by  hydrochloric  acid. 
See  Tachylite,  page  228. 


NOTE  ON  TABLE  XXVII. 

Many  of  the  minerals  placed  (to  avoid  risk  of  error  in  their  determination) 
in  the  present  Table,  belong  properly — on  account  of  their  difficult  fusibility 
or  slight  percentage  of  water—  to  preceding  Tables,  and  are  described  more 
fully  in  these  latter.  The  various  Micas,  Talc  and  Steatite,  Agalmatolite,  the 
Pinites,  &c. ,  are  examples.  See  more  especially  the  Note  to  TABLE  XXV. 

The  minerals  which  belong  essentially  to  the  present  Table  consist  for  the 
greater  part  of  zeolites — hydrated  silicates  of  very  characteristic  occurrence  in 
trappeari  or  basaltic  rocks.  With  these,  in  a  Determinative  grouping,  the 
boro-silicate  Datolite  may  be  conveniently  placed,  as  it  resembles  many 
zeolites  in  general  characters,  and  is  also  frequently  present  in  amygdaloidal 
traps.  The  zeolites,  as  the  name  implies,  either  swell  up  or  intumesce  on  the 
first  application  of  the  blowpipe-flame,  or  otherwise  melt  very  easily,  and 
generally  with  bubbling.  All,  when  reduced  to  powder,  are  readily  decom- 
posed by  boiling  hydrochloric  acid,  the  silica  separating  in  many  cases  in  a 
gelatinous  form.  The  presence  of  CaO,  BaO,  or  K20.  is  easily  ascertained  by 
the  pocket-spectroscope,  if  a  drop  of  the  solution  be  taken  up  in  a  small  loop 
of  platinum  wire  and  held  within  the  edge  of  a  Bunsen-flame.  As  a  rule, 
when  lime  and  potash  are  present  together,  the  red  and  green  Ca-lines  come 
out  first,  and  then,  as  these  fade  away,  the  red  K-line  comes  into  view. 

In  the  present  Note,  only  the  more  common  of  these  minerals  are  referred 
to,  the  crystallographic  and  other  characters  of  the  less  important  species 
being  given  in  sufficient  detail  in  the  Table.  The  commonly  occurring  species, 
as  regards  their  blowpipe  reactions,  fall  into  three  series,  as  follows  : 

§  1.  Fusible  quietly :  (a)  soda-species  :  Analcime,  Natrolite ;  (b)  barytic 
species  :  Harmotome. 

§  2.  Fusible  with  much  bubbling,  but  without  (or  without  marked)  intu- 
mescence* on  first  application  of  the  flame  :  Datolite  ;  Prehnite. 

§  3.  Curling  up  or  intumescing  on  first  application  of  the  flame  :  (a)  lime- 
potash  species :  Apophyllite,  Phillipsite  ;  (b)  gelatinizing  lime-species  :  Thom- 


*By  "intumescence"  is  meant,  here,  not  a  mere  expansion  of  the  substance,  but  a  throwing 
out  of  excrescences  or  curling  up  after  the  manner  of  borax.    Minerals  which  intumesce  in 
this  manner  on  the  first  application  of  the  flame,  fuse  afterwards  in  general  without  bubbling, 
and,  as  a  rule,  somewhat  slowly. 
19 


274  BLOWPIPE  PRACTICE:. 

sonite,  Scolecite,  Laumontite ;  (c)  non- gelatinizing  lime-species:  Chabasife, 
Stilbite,  Heulandite. 

The  leading  characters  of  these  species  are  given  in  the  Table,  but  neces- 
sarily in  brief  form  only  ;  a  few  additional  references  to  their  crystallization 
are  therefore  appended. 

Analcime,  in  most  examples,  is  at  once  recognized  by  its  crystals,  as  these 
are  generally  well-formed  and  easily  made  out.  They  belong  to  the  Regular 
System,  and  consist  either  of  the  trapezohedron  2-2  (measuring  131°  48'  36" 
over  long  or  axial  edges,  and  146°  26'  33"  over  intermediate  edges),  or  of  a 
combination  of  this  form  with  the  cube,  the  latter  commonly  predominating 
and  thus  having  each  angle  replaced  by  three  triangular  planes  (with  inclin- 
ation of  cube-face  on  abutting  2-2  face  measuring  144°  44').'  The  cleavage  is 
cubical,  but  very  indistinct.  In  the  spectroscope,  as  a  rule,  no  other  line  than 
a  strong  Na-line  is  observable  if  the  test-matter  be  carefully  freed  from 
accompanying  calcite. 

Crystallized  Natrolite  was  formerly  and  is  still  often  known  as  Mesotype, 
the  term  Natrolite  having  been  originally  limited  to  the  yellowish-brown, 
concentric-fibrous  variety,  then  regarded  as  distinct.  The  crystals  belong  to 
the  Rhombic  System,  but  are  frequently  acicular,  or  are  only  partially  formed 
(as  polar  planes)  at  the  extremities  of  the  fibres  of  which  ordinary  .examples 
are  so  commonly  composed.  When  distinctly  formed,  they  consist  of  a  nearly 
rectangular  prism  with  front  angle  (  — V  :  V)  of  about  91°,  terminated  by  the 
planes  of  a  somewhat  low  pyramid  or  octahedron  measuring  143°  20'  and 
142°  40'  over  polar  edges,  and  53°  20'  over  middle  edge.  P  on  V,  conse- 
quently, measures  116°  40'.  The  prism-planes  in  most  examples  are  striated 
vertically  (sometimes  very  coarsely),  and  occasionally  either  the  front  or  side 

edges  are  replaced  by  V  or  V.  In  the  spectroscope,  pure  examples  as  a  rule 
shew  only  a  strong  Na-line,  but  transitory  flashes  of  red  and  green  Ca-lines 
sometimes  appear. 

Harmotome,  a  barytic  zeolite,  is  in  general  readily  recognized  by  its  small, 
symmetrically  formed  cruciform  crystals,  although,  occasionally,  re-entering 
angles  in  these  are  more  or  less  inconspicuous  or  are  indicated  only  by  striae. 
The  crystallization  is  apparently '  Rhombic,  but  the  crystals  have  to  some 
extent  a  Tetragonal  aspect.  They  consist  commonly  of  a  rectangular  prism 

(composed  of  the  forms  V  and  V),  terminated  by  the  planes  of  an  octahedron 

or  pyramid,  P,  or  occasionally  by  those  of  a  side-polar  or  brachydoir  e  P.  In 
some  crystals,  the  polar  planes  are  simply  striated  ;  in  others,  the  V  planes 
shew  a  lozenge-shaped  striation.*  Two  (or  four)  of  these  crystals  form  inter- 
penetrating twins,  with  vertical  axis  in  common.  P  :  P,  over  polar  edges, 

120°  1'  and  120°  42' ;  P  :  P  110°  20'.  Cleavage,  V  distinct,  V  somewhat  less 
apparent.  A  drop  of  the  hydrochloric  acid  solution,  taken  up  in  a  loop  of 

*  Some  crystallographers  (after  Des  Cloizermx)  make  the  System  Clino-Rhombic,  and  regard 
this  front-vertical  form  as  the  basal  form.  On  that  view,  most  of  the  crystals  will  be  elongated 
in  the  direction  of  the  clino-axi». 


MINERAL  TABLES  : — XXVII.  275 

platinum  wire,  shews  the  green  Ba-lines  in  the  spectroscope  very  distinctly. 
The  diluted  solution  gives  also  a  marked  precipitate  with  a  drop  of  sulphuric 
acid. 

Datolite — a  hydrated  boro-silicate  of  lime— is  described  fully,  as  regards  its 
more  distinctive  characters,  apart  from  crystallization,  in  the  Table.  Its 
crystals  belong  to  the  Clino -Rhombic  system,  but  many  (the  Arendal  crystals 
especially)  are  strikingly  Ortho-Rhombic  in  aspect.  These  latter  are  chiefly 
in  the  form  of  rhombic  or  six-sided  tabular  crystals,  composed  of  the  forms  V 

and  V,  with  broadly-extended  basal  plane,  and  commonly  with  a  front-polar 
or  orthodome  (  -  2P)  and  other  polar  planes  subordinately  developed.  In 
many  crystals  these  polar  planes  appear  equally  at  corresponding  extremities, 
with  but  little  if  any  difference  in  their  angle  values,  and  thus  impart  an 
Ortho-Rhombic  character  to  the  crystal.  In  crystals  from  other  localities, 
however,  and  in  some  of  the  Arendal  crystals,  they  are  developed  only  at  one 
extremity.  In  the  Andreasberg  and  most  other  crystals,  the  basal  plane  is 
also  well-developed  as  a  rule,  but  the  prism-planes  (V,  V£,  and  V)  and  certain 

polar  planes  (especially  -  2P,    -  P,   and  the  side-polars  or  brachydomes  2  P 

and  4P)  are  also  well  formed,  and  the  crystals  are  thus  more  short-prismatic 
than  tabular.  In  some  crystals,  again,  the  basal  form  is  entirely  absent. 
The  principal^ angles  are  as  follows  :  V :  V  76°  38' ;  V£  :  V£  115°  22' ;  V :  Vfc 
160°  38' ;  B  :  V  90°  6'  (and  89°  54') ;  B :  -  2P  135°  4'.  The  marked  green  color- 
ation (from  the  presence  of  B203)  which  datolite  imparts  to  the  flame  of  the 
blowpipe  or  Bunsen  burner  serves  at  once  to  distinguish  it  from  other  minerals 
of  similar  aspect. 

Prehnite  is  distinguished  from  other  Zeolites  by  its  high  degree  of  hardness? 
( =  6  to  7),  and  its  small  percentage  of  water.  It  occurs  most  commonly  in 
botryoidal  masses  with  crystalline  surface  and  radio-fibrous  structure,  the 
colour  varying  from  pale  greenish-white  to  deep  apple-green.  Distinct  crys- 
tals are  comparatively  rare.  They  belong  to  the  Rhombic  System,  and  pre- 
sent four  types :  (1),  The  symmetrically  tabular  type — in  which  the  crystals 
arc  thin  rhombic  tables  composed  of  the  forms  V  and  B  ;  or  six-sided  tables 

composed  of  V  V  and  B  ;  or  eight-sided  tables  made  up  of  V,  V,  V,  and  B, 
the  basal  form  in  each  case  greatly  preponderating.  (2),  The  tabular  type 
with  brachydiagonal  elongation — in  which  the  thin  crystals  contain  the  forms 

V,  V  and  B,  and  are  greatly  extended  along  the  two  latter,  thus  passing  at 
times  into  fibrous  aggregations  with  the  two  front  planes  of  V  at  the  free  end 
of  the  fibres.  (3),  The  short-prismatic  type  with  development  of  side  or 
brachy-forms — the  crystals  of  this  type  being  composed  essentially  of  the 

forms  V  and  B,  with  V  and  3P  at  the  sides,  the  planes  of  the  rhombic  prism 
V  preponderating ;  and  (4),  The  short-prismatic  type,  with  front  or  macro- 
forms — the  crystals  presenting  the  forms  V  and  B,  as  preponderating  forms, 
with  the  front- vertical  V,  and  the  front- polar  or  rnacrodome  |P  subordinately 
developed,  in  addition  occasionally  to  the  planes  of  the  rhombic  pyramid  P,, 


276  BLOWPIPE    PRACTICE. 

forming  a  narrow  border  to  the  basal  plane.     V  :  V  99°  56' ;  B  :  3P  106°  3$ ; 

B  :  fP  134°  52'.  The  vertical  faces  are  frequently  convex,  whilst  the  basal 
plane  is  more  or  less  concave,  and  from  the  aggregation  of  these  curved  crys- 
tals, parallel  to  B,  globular  or  spheroidal  examples  commonly  arise.  For 
other  characteristics,  see  the  Table. 

Apophyllite  is  distinguished  chemically  by  its  fluorine  reaction,  by  the 
absence  of  alumina,  and  by  the  persistent  K-line  which  it  exhibits  in  the  spec- 
troscope when  moistened  with  hydrochloric  acid.  Its  Tetragonal  crystals  are 
in  general  distinctly  formed,  and  are  thus  easily  recognized.  They  present 
three  more  or  less  distinct  types  :  (1),  A  prismatic  type — in  which  the  crystals 
are  simple  square  prisms  (V,  B),  with  angles  replaced  by  the  triaxial  pyramid 
P ;  (2),  A  tabular  type — in  which  the  crystals  present  a  large  base,  with  V 
and  P  depressed  to  little  more  than  a  narrow  border  around  it ;  and  (3),  A 
pyramidal  type — in  which  the  pyramid  P  essentially^predominates,  although 
combined  with  the  front- vertical  form  or  pinakoid,  V,  and  occasionally  with 
the  octagonal  prism  V2  (which  appears  as  a  bevelment  on  the  vertical  edges  of 
V).  The  basal  plane,  with  its  peculiar  iridescent-pearly  lustre,  is  also  fre- 
quently present  in  this  type,  but  it  is  always  of  small  size,  and  the  general 
aspect  of  the  crystals  is  essentially  pyramidal.  P  :  P  over  polar  edge  104°  to 
104°  20',  over  middle  edge  120°  to  121°.  B  :  P  about  119°  30'.  The  cleavage 
is  basal  and  very  perfect,  the  points  of  the  pyramid  consequently  are  com- 
monly broken  off.  Twin  crystals,  so  commou  in  many  Zeolites,  are  in  this 
species  all  but  unknown. 

Phillipsite  is  also  a  potassic  species,  but  differs  from  Apophyllite  by  con- 
taining alumina,  as  well  as  by  the  absence  of  fluorine,  and  essentially  by  its 
crystallization.  It  differs  also  by  its  complete  gelatinization  in  hydrochloric 
acid.  Its  crystals  are  practically  identical  with  those  of  Harmotome  (see 

above),  and  thus  consist  essentially  of  a  rectangular  prism  (V,  V)  terminated 

id 
by  the  polar  forms  P,  P ;  two  (or  four)  crystals  being  united  in  cruciform 

twins.  In  some  crystals,  the  vertical  planes  look  like  those  of  a  simple  prism, 
but  the  compound  nature  of  the  crystal  is  revealed  by  the  re-entering  angles 
at  the  summit.  In  general,  however,  the  cruciform  character  of  the  crystals 

\j  %j 

is  sufficiently  distinct.  The  planes  of  the  forms  P,  P,  and  V,  are  transversely 
striated. 

Thomsonite  occurs  chiefly  in  fibrous  and  acicular  forms,  but  is  also  found  in 
small,  distinct  crystals.  These  belong  to  the  Rhombic  System,  and  present 
two  types  or  varieties  :  (1),  The  Thomsonite  type,  proper,  in  which  the  crys- 
tals are  short,  large-based,  vertically-striated  rhombic  prisms,  V,  replaced  on 

the  acute  edges  by  the  side  or  brachy-vertical  V,  and  on  the  obtuse  edges  and 
angles  by  the  front- vertical  V,  and  front-polar  or  macrodome  mP  ;  and  (2), 
The  Oomptomite  type,  in  which  the  crystals  form  short  eight-sided  prisms 

(composed  of  the  forms  V,  V,  V)  with  the  two  planes  of  an  exceedingly  flat 
brachydome  or  side-polar  l/mP  entirely  occupying  the  position  of  the  base.  The 


MINERAL    TABLES  : XXVII.  277 

prism  V  is  nearly  square,  its  front-angle  measuring  90°  40'.  The  flat  brachy- 
dome  planes  meet  (according  to  Des  Cloiseaux)  at  an  angle  of  177°  23'. 

Crystals  of  Scolecite  very  closely  resemble  those  of  Natrolite  or  Mesotype, 
as  they  consist  of  nearly  square  prisms  terminated  at  each  extremity  by  four 
pyramidal  planes.  But  whilst  Natrolite  crystals  are  clearly  Ortho-Rhombic, 
Scolecite  crystals  are  regarded  as  Clino-Rhombic,  the  pyramidal  planes  at  the 
top  and  bottom  of  the  crystal,  respectively,  differing  slightly  in  their  inter- 
facial  angles.  These  angles,  nevertheless,  closely  correspond  to  those  of 
Natrolite.  V  :  V  =  91°  35'  (in  Natrolite  91°) ;  P  :  P,  over  polar  edge  in  front, 
144°  20'  (in  Natrolite  143°  20') ;  -P  :  -P  144°  40'.  Occasionally  the  prism  is  six- 
sided,  its  acute  edges  being  replaced  by  "the  side-vertical  V,  Scolecite  differs, 
however,  essentially  from  Natrolite  in  being  a  lime-species  in  place  of  a  soda- 
species,  and  by  its  remarkable  blowpipe  comportment :  as,  whilst  Natrolite 
fuses  quietly,  Scolecite  expands  and  curls  up  or  throws  out  excrescences  on  the 
first  application  of  the  flame,  at  least  in  all  typical  examples.  Some  examples 
are  said  to  fuse  without  intumescence,  but  these  are  probably  soda-holding 
varieties,  or  Mesolite.  All  essentially  calcareous  zeolites  exfoliate  or  intumesce 
before  the  blowpipe,  or  otherwise  fuse  with  continued  bubbling.  Purely 
alcaline  zeolites,  on  the  other  hand  fuse  quietly. 

Laumontite  when  in  crystals  is  easily  recognized,  but  when  in  fibrous  masses 
it  is  distinguished  with  difficulty  from  other  calcareous  zeolites.  A  somewhat 
salient  character  is  its  great  tendency  to  fall  into  a  white,  earthy  powder  from 
efflorescence.  The  crystals  are  Clino-Rhombic,  and  they  consist  most  commonly 
of  a  simple  rhombic  prism  terminated  obliquely  by  a  single  plane.  The  latter 
is  the  basal  plane  of  most  French  crystallographers,  but  is  commonly  made 
the  plane  of  a  hemi-orthodome  or  front-polar  -P.  The  prism-angle  V  :  V,  in 
front,  equals  86°  16' ;  V  :  -P  =  1 13°  30'.  Very  frequently  the  opposite  angle  of 
the  prism  is  replaced  by  the  corresponding  hemi-orthodome  P,  the  latter 
inclining  to  a  face  of  the  prism  at  an  angle  of  104°  20'.  Often,  also,  other 
polar  planes  (P,  &c.)  are  subordinately  present,  and  the  vertical  edges  of  the 

prism  are  sometimes-  slightly  truncated  by  V  and  V.  Spectroscopic  and  other 
characters  are  given  in  the  Table. 

Chabasite  is  easily  distinguished  from  other  zeolites  by  its  rhombohedral 
crystallization.  The  crystals,  although  small,  are  in  general  distinctly  formed,. 
They  consist  essentially  of  cuboidal  rhombohedrons,  with  R  :  R  measuring 
over  polar  edges  94°  to  95°,  usually  94°  46',  whence  the  old  French  name  of 
zeolite  cubiqne  by  which  the  species  was  at  one  time  known.  In  many 
examples,  this  rhombohedron  occurs  in  the  simple  state,  but  very  often  its 
polar  edges  are  replaced  by  an  obtuse  rhombohedron  -  ^R^and  its  middle  angles 
by  the  acute  form  -  2R,  measuring  respectively  over  their  own  polar  edges, 
125°  13',  and  72°  53'.  R  on  -  £R  =  136°  23' ;  R  on  -  2R  =  1 19°  42'.  The  planes 
of  the  chief  rhombohedron,  R,  are  sometimes  striated  parallel  to  the  polar 
edges,  the  stride  meeting  in  the  line  of  the  longer  diagonal  of  each  plane.  These 
striae  indicate  a  very  obtuse  scalenohedron,  occasionally  present  in  Chabasite 
crystals.  An  obtuse  twelve-sided  pyramid  §P2  (with  angle  of  145°  over  polar 


278  BLOWPIPE    PRACTICE. 

edges)  is  the  predominating  form  in  the  Bohemian  variety  known  as  Phacolite. 
This  variety  occurs  in  interpenetrating  twins  ;  and  twin-forms,  with  the 
vertical  axis  in  common,  are  of  frequent  occurrence  in  crystals  of  Chabasite 
generally.  The  solution  in  hydrochloric  acid,  in  which  the  silica  separates  in 
a  slimy  or  at  times  in  almost  a  gelatinous  condition,  shews  in  the  spectroscope 
a  vivid  calcium  spectrum,  and  as  this  fades  out  a  transitory  red  K-line  generally 
comes  into  view. 

Stilbite  and  Heulandite  may  in  general  be  distinguished  easily  from  other 
zeolites  by  their  almost  constant  occurrence  in  bladed  or  narrow -foliated 

examples,  with  very  perfect  cleavage  in  one  direction  and  strong  pearly  lustre 

i  > 
on  the  cleavage  surface.     The  latter  is  parallel  to  a  side- vertical,  V,  or  (in 

Heulandite)  V.  The  hardness,  also,  is  lower  than  in  most  other  zeolites,  viz.c 
3'5-4'0.  The  free  ends  of  the  foliae  generally  shew  crystalline  facets.  The 
colour  is  commonly  either  white,  red,  or  light-brown.  In  Stilbite,  the  crystal- 
system  is  Rhombic,  and  the  more  common  crystals  consist  of  a  rectangular 

prism  (V,  V,  usually  flattened  parallel  to  V,  the  cleavage  plane),  with  the 
planes  of  a  rhombic  octahedron,  P,  at  each  extremity.  Occasionally,  the 
vertical  edges  of  the  rectangular  prism  are  slightly  replaced  by  the  rhombic 
prism  V,  and  the  point  of  the  octahedron  is  truncated  by  the  basal  form  B. 
The  prism-angle,  V  :  V,  equals  94°  16' ;  P :  P  over  front  polar  edge,  119°  16' ;. 
over  side  polar  edge,  114°  ;  over  middle  edge,  96°. 

In  Heulandite,  the  system  is  Clino-Rhombic.     The  more  commonly-occurring 

crystals  .are  made  up  of  the  front-vertical  form  V,  the  side  or  clino- vertical  V, 
the  front-polar  or  hemi-orthodome  P,  and  the  basal  form  B.  The  side- vertical 

V  (the  cleavage  plane)  generally  predominates,  the  crystals  being  usually 
much  flattened  in  that  direction  ;  but  occasionally,,  crystals  are  elongated 
transversely,  i.e,,  in  the  direction  of  the  ortho-diagonal  or  right-and-left  axis, 
in  which  case  the  frontal  forms  V  and  P  preponderate.  The  hemi-pyramids 

2P  and  §P,  and  the  clinodome  or  side-polar  2P,  also  occasionally  occur  as  sub- 
ordinate forms.  P:V  equals  129°  40' ;  B :  V,  116°  20';  2P:2P,  in  front,. 

J36°  4' ;  §P  :  |P,  146°  52' ;  2P  :  2P,  over  summit,  98°  44'. 

Although  both  Stilbite  and  Heulandite  are  essentially  lime  species,  they 
usually  contain  small  amounts  of  soda  and  potash.  When  a  drop  of  the-, 
hydrochloric-acid  solution  (taken  up  in  a  loop  of  clean  platinum  wire)  i& 
examined  by  the  spectroscope,  the  red  K-line,  therefore,  almost  always 
appears  for  an.  instant,  a,s  the  vivid  re.d  an,d.  green  Ca-Uues  fade  out  of 


INDEX 

TO  THE   MINERALS   IN  PART  II. 


Abichite,  144. 
Abrazite  (v.  Gismondine). 
Acadialite,  268. 
Acanthite,  107, 
Acanticone  (v.  Epidete), 
Acmite,  232. 
Actinolite,  233. 
Adamvantine  Spar,  196,  207. 
Adamite,  145. 

Adularia  Feldspar,  245,  253. 
^Edelforsite,  272. 
.^Egirine,  233. 
^schynite,  126. 
Agalmatolite,  219. 
Agaric  Mineral  (v.  Calcifce). 
Agate,  20& 
Aikinite,  107. 
Alabandine,  108,  124,  152. 
Alalite,  243. 
Albertite,  132, 
Albin,  268. 
Albite,  246,  254. 
Alexandrite  (v.  Chrysoberyl)- 
Algodonite,  10L 
Alipite,  217. 
Alisonite,  107. 
Allauite,  228. 
Allemontite,  101. 
Allochroite,  228, 
Alloclase,  103. 
Allophane,  217. 
Almandine,  230, 
Alstonite,  137. 
Altaite,  113. 
Alum,  154. 
Alumstone,  155. 
Aluminite,  155,  162. 
Alunite,  155. 
Alunogene,  154, 
Amalgam,  115. 
Amazon-stone,  246, 
Amber,  132,  133. 
Amblygonite,  164. 
Amethyst,  202,  208. 
Amianthus,  243. 
Ammonia- alum,  154. 
Amphibole,  233,  243,  251. 


Amphigene  (Lencite),  203. 
Analcime,  265,  274. 
Amatase,  127,  129,  196,  206. 
Anauxite,  219. 
Andalusite,  199,  210. 
Andesiue,  253. 
Andradite,  230. 
Anglarite  (v.  Viviamte), 
Anglesite,  151,  160. 
Anhydrite,  152,  16L 
Ankerite,  136. 
Annabergite,  145. 
Anorthite,  241. 
AnthophyUite,  216. 
Anthosiderile,  257, 
Anthracite,  128,  223. 
Anthraconirbe  (v.  Calcite), 
Antigorite,  215. 
Antimony,  113. 
Antimony  Blende,  149. 
Antimony  Glance,  110,  112. 
Antimonial  Silver  (v.  Dyscra- 


Antimonial  Nickel  Glance,  110, 
Antimonial  Nickel  Ore,  114. 
Antimony  Ochre,  149L 
Antimonite,  149. 
Antrimolite,  266, 
Apatelite,  158. 
Apatite,  1£3.  169, 
Aphancse,  144. 
Aphrodite  (Meerschaum?) 
Aphrosiderite,  257. 
Aphthalose,  153, 
Apthonite  (Tetrahedrite  ?) 
Apjohnite,  158, 
Aplome,  230. 
Apophyllite,  267,  276. 
Aquamarine  (Beryl),  200, 
Arseoxene,  144. 
Aragonite,  138,  141. 
Arcanite,  153. 
Arfvedsonite,  234. 
Argentite,  107,  109. 
Arkansite,  127. 
Arksutite,  178. 
Arquerite,  115. 


280 


INDEX. 


Arragonite,  138,  141. 

Arsenic,  101. 

Arsenical  Iron,  101. 

Arsenical  Pyrites,  103,  104. 

Arsenious  Acid,  )  ,  ,„ 

Arsenolite, 

Arseniosiderite,  146. 

Asbestus,  243. 

Asbolan,  189. 

Asmanite,  201, 

Asparagus  stone  v.  Apatite). 

Aspasiolite,  220. 

Asperolite,  217. 

Asphalt,  132. 

Aspidolite  (Magnesia  Mica). 

Astrakanite,  154. 

Astrophyllite,  227. 

Atacamite,  176,  177. 

Atelesite,  145. 

Atelite,  176. 

Atheriastite. 

Atlasite,  176. 

Auerbachite,  198. 

Augelite,  168. 

Augite,  232. 

Aurichalcite,  136. 

Auripigment  (v.  Orpinieiit). 

Automolite,  197. 

Autunite,  166. 

Avanturine  ( =  Quartz  with  in- 

spersed  scales  of  mica, 

iron-glance,  &c.). 
Axinite,  230,  248. 
Azurite,  135,  142. 

Babingtonite,  233. 
Bagrationite,  228. 
Baikalite  (Amphibole). 
Baltimorite,  221. 
Bamlite  (var.  Sillimanite),  200. 
Barnhardtite,  105. 
Barrandite  (Strengite  ?),  165. 
Barytine,  152,  160. 
Barium  Mica,  261. 
Baryto-calcite,  137,  153. 
Baryto-celestine,  152. 
Bastite,  215. 
Batrachite,  204. 
Baudisserite,  139. 
Beaumontite,  269. 
Bechilite,  172. 
Beraunite,  165. 
Bergemannite,  266. 
Berlinite,  168. 
Berthierite,  110. 
Beryl,  200,  209. 
Berzelite,  146. 
Berzeline,  106,  236. 


Beudantite,  144, 

Beyrichite,  105. 

Bieberite,  157. 

Bindheimite,  150. 

Binnite,  lt)3,  104. 

Biotite,  213. 

Bismuth,  115. 

Bismuthine,  j  10-    lf)Q 

Bismuth  Glance,  (  1U/>  luy' 

Bismuth  Ochre,  188. 

Bismutite,  136. 

Bitter  Salt  (Epsomite),  154. 

Bitter  Spar,  138. 

Bitumen,  132. 

Bituminous  Coal,  132,  134. 

Black  Band,  141. 

Black  Oxide  of  Copper,  116. 

Black  Jack,  109. 

Blende,  108,  109,  151,  159. 

Bloedite,  154. 

Bloodstone  (v.  Quartz). 

Blue  carb.  copper,  135. 

Blue  Vitriol,  156. 

Bodenite,  228. 

Bog  Iron  Ore,  193. 

Bog  Manganese  Ore  (Wad),  188. 

Bolognese  Spar  (Barytine),  152. 

Boltonite,  204. 

Bombiccite,  133. 

Bonsdorffite,  220. 

Boracite,  171,  173. 

Borax,  171,  173. 

Bornite,  105,  108. 

Borocalcite,  172. 

Boronatrocalcite,  172. 

Boracic  Acid,  171. 

Botryogene,  157. 

Botryolite,  270. 

Boulangerite,  111. 

Bournonite,  111,  112. 

Bowenite,  221. 

Bragite,  127. 

Brandisite,  216. 

Braumte,  125. 

Breislakite,  232. 

Breithauptite,  114. 

Breunnerite  (Mesitine),  136. 

Brevicite,  266. 

Brewsterite,  268. 

Brittle  Silver  Ore,  110. 

Brochantite,  158. 

Bromargyrite,  175. 

Bromlite,  137. 

Brongniardite,  111. 

Brongniartine  (v.  Glauberite). 

Bronzite,  216. 

Brookite,  127,  199. 

Brown  Coal,  132. 


INDEX. 


281 


Brown  Iron  Ore,  125,  128,  187, 

192. 

Brucite,  190,  194. 
Brushite,  168. 
Bucholzite,  200. 
Bucklandite,  231. 
Bunsenite,  190. 
Buratite,  136. 
Buntkupfererz,  105. 
Bustamite,  233. 
Byssolite,  227. 
Bytownite  (var.  Anorthite). 

Cabrerite,  145. 
Cacholong  (var.  Opal). 
Cacoxene,  165. 
Cairngorm,  208. 
Calaite,  167,  170. 
Calamine,  205,  219. 
Calamite  (Tremolite),  243. 
Oalaverite,  113. 
Calcedony,  208. 


Calcite, 


137,  140. 


Calc  Spar, 

Caledonite,  135,  151. 
Calomel,  176. 

Canaanite  (var.  Pyroxene). 
Caiicrinite,  239. 
Cantonite  (Covelline  ?). 
Caporeianite,  272. 
Carbonado,  196. 
Carminite,  144. 
Carnallite,  174. 
Carnelian,  208. 
Carpholite,  266. 
Cassiterite,  127,  195,  206. 
Castor,  235. 
Cat's-Eye,  208. 
Celestine,  152,  160. 
Cerargyrite,  175,  177. 
Cerine,  228. 
Cerite,  205,  218. 
Cerussite,  135,  142. 
Cervantite,  149. 
Ceylanite,  197. 
Chabasite,  268,  277. 
Chalcanthite,  156. 
Chalcedony,  208. 
Chalkosine,  106. 
Chalilite,  265. 
Chalcanthite,  156. 
Chalcophanite,  126. 
Chalcophyllite,  144. 
Chalcopyrite,  105,  108. 
Chalcolite,  166. 
Chalcotrichite  (—  Acicular  Cu- 
prite). 
Chalcosiderite,  166. 


Chalcosine,  )  irw»   1no 
Chalkosine,  |  106'  109' 
Chalcostibite,  111. 
Chalibite,  265. 
Chalybite  (Siderite),  136. 
Chatamite,  101. 
Chamosite,  256. 
Chessylite,  135. 
Chesterlite  (Orthoclase). 
Chiastolite,  199,  223. 
Childrenite,  165. 
Chile  Saltpetre,  181. 
Chiolite,  178. 

Chladnite  (Meteoric  Enstatite). 
Chloanthite,  101. 
Chlor- Apatite,  163. 
Chlorastrolite,  267. 
Chlorides  (v.  TABLE  XIX. ). 
Chlorite,  314,  224,  257. 
Chloritoid,  259. 
Chloroealcite,  174. 
Chloromelane  (Cronstedite), 

256. 

Chloropal,  218. 
Chlorophceite,  260, 
Chlorophane  Fluor  Spar). 
Chlorophyllite,  215. 
Chlorotile,  144. 
Choudro-arsenite,  146. 
Ckondrodite,  204,  211. 
Chonikrite,  269. 
Christbphite,  151. 
Chromic  Iron  Ore,,  118,  124,  128. 
Chromite,  118,  124,  128,  186, 

192. 

Chrome  Garnet,  198. 
Chrome  Mica,  213. 
Chrysoberyl,  197,  207. 
Chrysocolla,  217. 
Chrysolite,  204,  210. 
Chrysoprase,  208. 
Chrysotile,  221. 
Churchite,  168. 
Cimolite,  219. 

Cinnabar,  121,  122,  130,  131. 
Cinnamon -stone  (Garnet). 
Clarite,  103. 
Claudetite,  148. 
Clausthalite,  106. 
Clay  Ironstone,  136,  141. 
Cleavelandite,  246. 
Clinoclase,  144,  147. 
Clinochlore,  214. 
Clino-Humite,  204. 
Clintonite,  216. 
Clathalite,  265. 
Coals,  132,  134. 
Cobalt  Bloom,  145. 


282 


INUEX. 


Cobalt  Spar,  137. 

Cobalt  Vitriol,  157. 

Cobaltine,  103,  104. 

Coccinite,  176. 

Coccolite,  232. 

Collyrite,  220. 

Colophonite,  245. 

Colunibite,  126. 

Comptonite,  271,  276. 

Cookeite,  261. 

Copiapite,  158. 

Copper,  116. 

Copper  Binnite,  103. 

Copper  Glance,  106,  109. 

Copper  Mica,  144. 

Copper  Nickel  (Nickeline),  101, 

102. 

Copper  Pyrites,  105,  108. 
Copper  Uraiiite,  106,  170. 
Copper  Vitriol,  156. 
Copperas  (Green  Vitriol),  156. 
Coquimbite,  157. 
Coracite,  190. 
Cordierite,  200,  211. 
Corneous  Lead  Ore,  176. 
Cornwallite  (a  copper  arseniate). 
Corundum,  196,  297. 
Corynite,  103. 
Cosalite,  J07. 
Cotunnite,  176. 
Couserauite,  241. 
Covelline,  130. 
Crednerite,  126. 
Crichtonite  (Ilmenite),  118. 
Crocidolite,  259. 
Crocoisite,  182,  184. 
Cronstedite,  256. 
Crookesite,  106. 
Cryolite,  178. 
Cryophyllite,  235. 
Cryptolite,  164. 
Cryptomorphite,  172. 
Cubanite,  105. 
Cube  Ore,  145. 
Cuboite,  265. 
Culsageeite,  362. 
Curnniingtonite,  234. 
Cuprite,    116,    122,    123,   189, 

193. 

Cuproplurabite,  107. 
Cyanite,  197,  210. 
Cymophane,  197. 
Cyprine,  245. 

Damourite,  260. 
Pauaite,  103. 
Danalite,  229. 
Danburite,  236. 


Dark  Red  Silver  Ore,  110,  112, 
121. 

Datolite,  270,  275. 

Daubreite,  176. 

Davyne,  239. 

Davidsonite  (Beryl). 

Dawsonite,  139. 

Dechenite,  182. 

Delessite,  214,  257. 

Delvauxite  (a  linie-iron  phos- 
phate). 

Demidowite,  217. 

Descloizite,  182. 

Desinine,  269. 

Deweylite,  221, 

Diadochite,  159. 

Diallage,  242. 

Diallogite,  137. 

Diamagnetite,  124. 

Diamond,  196,  206. 

Diam'te,  196. 

Diaphorite,  111. 

Diaspore,  196. 

Dichroite,  200,  211. 

Dihydrite,  167. 

Diopside,  243. 

Dioptase,  205,  216. 

Diphauite,  215. 

Dipyre,  241. 

Disterrite  (Brandisite),  216. 

Disthene,  197,  210. 

Dolomite,  138,  140. 

Domeykite,  101. 

Donacargyrite,  111. 

Dopplerite,  132. 

Dufrenite  (Green  Iron  Ore,  an 
iron  phosphate). 

Dufrenoysite,  103,  104. 

Durangite,  147. 

Dyscrasite,  113. 

Dysluite  (Gahnite),  197. 

Edingtonite,  264. 

Egerane,  244. 

Ehlite,  166. 

Ekebergite  (Warnerite),  240. 

Elseolite,  239. 

Elastic  Bitumen,  132. 

Elaterite,  232. 

Electrum  (Amalgam),  115. 

Eliasite,  190. 

Embolite,  175. 

Emerald,  200,  209. 

Emerald-Nickel  (Zaratite),  139. 

Emery,  196,  207. 

Emery  lite,  215. 

Emplectite,  107. 

Enargite,  103. 


INDEX. 


283 


Enstatite,  201. 
Epichlorite,  214. 
Epidote,  231,  249. 
Epigenite,  103. 
Epistilbite,  269. 
Epsomite,  154. 
Erdmaimite,  228. 
Eremite,  765. 
Erinite,  144. 

Erubescite  (Bornite),  10.5. 
Erythrine,  145. 
Esmarkite,  220. 
Essonite  (Garnet), 
Ettringite,  156. 
Euchroite,  144. 
Euclase,  200. 
Eucolite,  237. 
Eudialyte,  237. 
Eudnophite,  265. 
Eukairite,  106. 
Eulytine,  237. 
Euphyllite,  215. 
Eupychroite,  163. 
Eusynchite,  182. 
Euxenite,  127. 
Euzeolite,  269. 
Evaiisite,  167. 

Fahlerz,  110. 
Fahlunite,  220. 
Fargite,  266. 
Farcolite,  272. 
Fassaite,  232. 
Faujasite,  267. 
Fauserite,  158. 
Fayalite,  227. 
Feather  Alum,  157. 
Feldspar  (lime),  241. 
Feldspar  (potash),  245. 
Feldspar  (soda),  245. 
Feldspar  Group,  253. 
Felsobanyite,  155. 
Fergusonite,  127. 
Fibro-Ferrtfe,  158. 
Fibrolite,  200. 
Fichtelite,  133. 
Figure  Stone,  219. 
Fire  Blende,  149. 
Fire  Opal,  202. 
Fischerite,  167. 
Flint,  208. 
Flos  Ferri,  138. 


Fluellite,  178. 

Fluocerite,  179. 

Fluor-Apatite,  163,  169. 

Fluorite,  178. 

Fluor  Spar,  178,  179. 

Foresite  (near  Stilbite),  269. 

Forsterite,  204. 

Fowlerite,  233. 

Francolite,  163. 

Franklinite,  118,  124,  128,  186, 

192. 

Freislebeiiite,  111. 
Frenzelite  (Guanajuatite),  106. 
Frugardite,  245. 
Fuchsite,  213. 

Gadolinite,  204. 
Gahiiite,  197,  208. 
Galactite,  266. 
Galena,  107,  109. 
Galmei  (Calamine),  205. 
Garnet,  230,  141. 
Garnet  Group,  248. 
Gaylussite,  138. 
Gehlenite,  204. 
Geierite,  103. 
Genthite,  217. 
Geocerite,  133. 
Geocronite,  112. 
Gersdorffite,  103. 
Gibbsite*  (see  Note,  below). 
Giesseckite,  220. 
Gigantolite,  266. 
Gilbertite,  215. 
Gillingite  (Hisingerite),  218. 
Giobertite,  138. 
Girasol,  202. 
Gismondiiie,  271. 
Glagerite,  220. 
Glaserite,  153. 
Glauberite,  153. 
Glauber's  Salt,  153. 
Glaucodot,  103. 
Glauconite,  259. 
Gla'ucophane,  244. 
Glingite,  204. 
Glockerite,  158. 
Gmelinite,  271. 
Gcethite,  125. 
Gold,  116. 

Gold- Amalgam,  115. 
Goschenite  (v.  Beryl). 


*  Accidentally  omitted  from  foot  of  page  220,  where  it  should  follow  Kollyrite  : 
GIBBSITE  (Hydrargillit.-)  :— AJ«O'  65-5,  WO  34'5.      In  small  hexagonal  crystals  with   basal 
cleavage,  or  in  mammary  or  stalactitic.  examples  of  a  white,  greenish-yellow,  or  other  light 
colour.     II  2-5-30;  G  '2-3-2'4.     BB,  infusible,  but  commonly  exfoliates.     In  powder,  dissolved 
by  caustic  potash  ;  also  by  sulphuric  acid. 


284 


INDEX. 


Goslarite,  155. 

Grahamite,  122. 

Gramenite,  218. 

Grammatite,  243. 

Graphic  Tellurium,  113. 

Graphite,  117. 

Green  Carb.  Couper,  135. 

Green  Earth,  258. 

Green  Vitriol,  156. 

Grey  Antimony  Ore,  llO,  112. 

Grey  Copper  Ore  (Tetrahedrite), 

110. 

Greenockite,  151. 
Greenovite  Sphene),  229. 
Grengesite  (near  Delessite),  257. 
Grophite,  215. 
Groroih'te,  188. 
Grossular,  241. 
Guadalcazarite,  106,  107. 
Guanajuatite,  106. 
Guarinite,  239. 
Gummite,  190. 
Gurhofian,  138. 
Gymnite,  221 
Gypsum,  155,  161. 
Gyrolite  ( ApophyUite  ? ),  '267. 

Haarkies  (Millerite),  105. 
Haematite,  118,  120,  114,  128. 
Haidingerite,  146. 
Halite  (Rock  Salt),  174,  177. 
Hallite,  262. 
Halloysite,  220. 
Halotrichite,  157. 
Harmatite,  179. 
Harmatome,  264,  274. 
Harringtonite,  266. 
Hartite,  133. 
Hatchettine,  133. 
Hauerite,  108,  124,  152. 
Hausmannite,  125. 
Hauyne,  246. 
Haydenite,  268. 
Haytorite  (Quartz  in  pseudo- 

morphs  after  Datolite). 
Heavy  Spar,  152,  160. 
Hebronite,  164. 
Hedenbergite,  232. 
Hedyphane,  144. 
Heliotrope  (Bloodstone),  208. 
Helminthite,  214. 
Helvine,  229. 
Helvetaue,  261. 
Hematite,  118,  120,  124,  128. 
Hercynite,  198. 
Herderite,  164. 
Herrerite,  137. 
Herschelite,  268. 


Hessite,  113. 
Hessonite  (Garnet). 
Heterogenite,  189. 
Heterosite,  166. 
Heulandite,  269,  278. 
Hjelmite,  127. 
Hisingerite,  218,  258. 
Hoernisite,  146. 
Homichline,  105. 
Hopeite,  168. 
Horbachite,  105. 
Hornblende,  233. 
Horn  Silver  Ore,  175,  177. 
Horseflesh  Ore,  108. 
Hortonolite,  284. 
Hovite,  139. 
Hubnerite  (Wolfram). 
Humboldtilite,  238. 
Humboldtine,  187, 
Humboldtite,  270. 
Humite,  204 
Hunterite,  219. 
Hureaulite,  166. 
Hyacinth,  198. 
Hyalite,  209. 
Hyalophane,  236,  246. 
Hyalosiderite,  228. 
Hydrargillite  (see  Foot-note  to 

Gibbsite). 

Hydroboracite,  172. 
Hydrocuprite,  189. 
Hydrodolomite,  139. 
Hydrofluocerite,  139. 
Hydrohematite,  125. 
Hydromagnesite,  138. 
Hydrophane  (var.  Opal). 
Hydrotachylite,  273. 
Hydrozincite,  139. 
Hypersthene,  232. 

Iberite,  220. 

Ice-spar  (var.  Orthoclase). 

Iceland  Spar  (var.  Calcite). 

Idocrase,  244,  249. 

Idrialine,  130. 

Iglesite,  135. 

Ilmenite,  118,  120,  125,  128, 

186,  192. 
Ilvaite,  228,  250. 
Indicolite,  199. 
lodargyrite,  175. 
lolite,  200,  211. 
Iridium,  117. 
Iridosrnine,  117. 
Iridosmium,  117. 
Iron,  117. 
Iron  Alum,  157. 
Iron  Chrysolites,  250. 


INDEX. 


285 


Iron  Glance,  118,  120. 
Iron  Pyrites,  105,  108. 
Ironstone,  140. 
Isoclase,  168. 
Ittiierite,  270. 
Ixolyte,  132. 

Jacobsite,  118,  186. 
Jamesonite,  111,  112. 
Jargon  (Zircon),  198. 
Jarosite,  159. 
Jasper,  208. 
Jeflerisite,  362. 
Jeffersoiiite,  233. 
Jenite  (Lievrite),  228,  250. 
Jet,  132. 
Johannite,  157. 
Jordanite,  104. 

Kammercrite,  214. 
Kalaite  (Turquoise). 
Koinite,  154. 
Kakoxene,  165. 
Kalinite,  154. 
Kampylite,  144. 
Kaolin,  219,  225. 
Karminspath,  144. 
Karstenite  (Anhydrite),  152. 
Kastor,  215. 
Keilhauite,  230. 
Kenngottite  (var.  Miargyrite). 
Keragyrite,  175,  177. 
Kerasine,  135,  176. 
Kermesite,  121,  123,  149. 
Kerolite,  221. 

Kibdelophane  (Ilmenite),  118. 
Kieserite,  155. 
Kilbrickenite,  112. 
Killiiiite,  262. 
Kirwanite,  260, 
Kjerulfine,  163. 
Klaprothiiie  (Lazulite),  168. 
Klipsteinite,  264. 
Knebelite,  229. 
Kobellite,  112. 
Kosttigite,  145. 
Kollyrite,  220. 
Konite,  130. 
Kottigite,  145. 
Kongsbergite,  115. 
Koiileinite,  133. 
Korundophyllite,  214. 
Koupholite,  267. 
Krantzite,  132. 
Kraurite  (Green  Iron  Ore,  an 

iron  phosphate). 
Kreittonite,  197. 
Kremersite,  175. 


Krisuvigite,  158. 
Krokidolite,  259. 
Kuhnite,  146. 
Kyanite,  197. 

Labradorite,  241. 
Labrador  Feldspar,  241. 
Lagonite,  172. 
Lampadite,  189. 
Lanarkite,  151. 
Lancasterite,  139. 
Langite,  158. 
Lanthanite,  139. 
Lapis  Lazuli,  237. 
Larderellite,  172. 
Latrobite  (var.  Anorthite). 
Launiontite,  272,  277. 
Laxmannite,  182. 
Lazulite,  168. 
Lead,  115. 
Lead  Binnite,  104. 
Lead  Glance,  107,  109. 
Leadhillite,  135. 
Leafy  Tellurium  Ore,  111. 
Lehrbachite,  106. 
Lehuntite,  266. 
Lenzinite,  220. 
Leonhardite,  272. 
Lepidochrocite,  125,  187. 
Lepidokrokite,  125,  187. 
Lepidolite,  230,  234,  247. 
Lepidomelane,  227. 
Lettsomite,  158. 
Leuchtenbergite  (Ripidolite), 

214. 

Leucite,  203,  212. 
Leucophane,  178,  240. 
Leucopyrite,  101. 
Levyne,  268. 
Libethenite,  167,  170. 
Liebenerite,  220. 
Liebigite,  139. 
Lievrite,  228,  250. 
Lignite,  132. 
Ligurite  (Sphene),  229. 
Lillite,  257. 
Lime  Uranite,  166. 
Limonite,  125,  128. 
Linarite,  158. 
Lincolnite,  269. 
Lindakerite,  139. 
Linno3ite,  105. 
Liroconite,  144,  147. 
Litharge,  187. 
Lithia  Mica,  234. 
Liver  Ore,  131. 
Lobolite,  245. 
Lollingite,  101. 


28* 


INDEX. 


Lcewite,  154. 

Loxoclase  (var.  Orthoclase). 

Ludlamite,  165. 

Ludwigite,  171. 

Lutiebergite,  168. 

Lunnite  (Phosphorchalcite),  167. 

Luzonite,  103. 

Magnesia  Alum,  154. 
Magnesite,  138,  140. 
Magnetic  Iron  Ore,  118,  120, 

124,  128,  186. 

Magnetic  Pyrites,  105,  108. 
Magnetite,  118,  120,  124,  128, 

186. 

Magnoferrite.  186. 
Malachite,  135,  142. 
Malacolite,  243. 
Malakon,  198. 

Maldonite  (  =  Bismuthic  Gold). 
Mangan  Blende  (Alabandine, 

124). 

Manganite,  119,  120,  125. 
Manganese  Alum,  158. 
Manganese  Spar,  137. 
Manganese  Vitriol,  158. 
Marble,  140. 
Marcasite,  105,  108. 
Margarite,  215. 
Margarodite,  261. 
Marmatite,  151. 
Marmolite,  221. 
Martite,  118. 
Mascagnine,  153. 
Maskelynite  ( =  Meteoric  Labra- 

dorite). 

Masonite,  259. 
Massicot,  187. 
Matlockite,  176. 
Maxite,  135. 
Medjidite,  157. 
Meerschaum,  221. 
Mcgabromite,  175. 
Meionite,  240. 
Melaconite,  189. 
Melanglance,  110. 
Melanite  (Black  Garnet). 
Melanolite,  258. 
Melanochroite  (Phoenicite),  182. 
Melanterite,  156. 


Melilite,  238. 

Melinophane,  178,  240. 

Meliphanite,  178,  240. 

Meionite,  114. 

Melopsite   (near  Deweylite), 
221. 

Menaccanite,  118. 

Mendipite,  176. 

Meneglmite,  111. 

Mengite,  126. 

Menilite,  202. 

Mennige,  187. 

Mercury,  115. 

Mesitine,  136. 

Mesolite,  266. 

Mesotype,  265. 

Metabrushite,  168. 

Metachlorite,  214,  256. 

Metacinnabarite,  107. 

Metaxite,  221. 

Meteoric  Iron,  117. 

Miargyrite,  110,  121. 

Micas,  213,  224. 

Microbromite,  175. 

Microcline,  246. 

Microlite  (Pyrochlore),  126. 

Microsommite,  237. 

Millerite,  105. 

Miloschin,  218. 

Mimetesite,  144,  148. 

Minium,  187. 

Mirabilite,  153. 

Mispickel,  103,  104. 

Mizzonite,  241. 

Molybdenite,  107,  109. 

Molybdic  Ochre,  183. 

Monazite,  165. 

Monrolite,  200. 

Montebrasite,  164. 

Moiiticellite,  204. 

Moonstone  ( =  Opalescent  Feld- 
spar). 

Morenosite,  157. 

Moroxite  (var.  Apatite),  163. 

Mosandrite* 

Mottramite,  184. 

Mountain  Cork,  258. 

Mountain  Wood,  258. 

Miillerine,  113. 

Mimetic,  105. 


*  Accidentally  omitted  from  Table  XXVII.,  immediately  following  Heulandite,  as  annexed : 
(H  4'0 ;  streak  distinctly  yellow  or  brownish;  decomposed  l>y  hydrochloric  acid  with 

production  of  chlarin e  fum cs). 

MOSANDKITE  :— Essential  components:  Na2O,  CaO,  MnO,  Cc203  with  Di2O3  and  La208,  TiO2, 
SiO2,  H2O.  Rhombic  (?),  but  mostly  in  broad-fibrous  or  lameUar  masses  of  a  reddish-brown 
colour;  G  2'9-3'0.  BB  intumesces  and  fuses  readily  into  a  yellowish-brown  bead.  The  hydro- 
rhloric-acid  solution  is  reddish-yellow,  but  becomes  paler,  and  evolves  chlorine,  on  heating. 
A  very  rare  species. 


INDEX. 


287 


Muromontite,  228. 
Muscovite,  213,  224. 

Nacrite,  219. 
Naclorite,  150. 
Nagyagite,  111. 
Nantokite,  175. 
Nasturane,  127. 
Native  Antimony,  113. 
N.  Arsenic,  101,  102. 
N.  Bismuth,  101,  115. 
N.  Copper,  116. 
N.  Gold,  116. 
N.  Iridium,  117. 
N.  Iron,  117. 
N.  Lead,  115. 
N.  Mercury,  115. 
N.  Palladium,  117. 
N.  Platinum,  117. 
N.  Silver,  116. 
N.  Sulphur,  130. 
N.  Tellurium,  113. 
Natrolite,  235,  274. 
Natron,  138. 
Naumanm'te,  106. 
Needle  Ore,  107. 
Neftgil,  133. 
Nemalite,  190. 
Nepheline,  239. 
Nephrite,  243. 
Newjanskite,  117. 
Nickel  Glance,  110. 
Nickel  Green,  145. 
Nickel  Gymnite,  217. 
Nickel  Vitriol,  157. 
Nickeline,  101,  102. 
Nigrescite,  260. 
Nigrine,  127. 
Niobite  (Coluuibite),  126. 
Nipholite,  178. 
Nitratiiie,  181. 
Nitre,  181. 
Nitrocalcite,  181. 
Nitromagnesite,  181. 
Nontronite,  218. 
Nosean,  236. 
Nosine,  236. 
Nuttalite,  241. 

Obsidian,  247. 
Ochres  : 

Bismuth  0.,  188. 

Manganese  0.  (Wad),  188. 

Molybdic,  O,,  183. 

Bed  0.,  186,  192. 

Tungstic  0.,  183. 

UranO.,  190. 

Yellow  0.,  187. 


Octahedrite,  127,  199. 

(Ellacherite,  261. 

Oerstedite,  198. 

Okenite,  268. 

Olafite,  246. 

Oligoclase,  246. 

Oligon  Spar,  136. 

Olivenite,  143,  147. 

Olivine,  204,  210. 

Omphazite  (Var.  Pyroxene). 

Onkosine  (compact  magnesian 
mica?  Related  to  Phlogo- 
pite  or  Biotite,  as  Steatite 
to  Talc). 

Onofrite,  106. 

Onyx  (Agate),  208. 

Opal,  202,  208. 

Ophiolite,  225. 

Orangite,  218. 

Orpiment,  130,  131. 

Orthite,  228. 

Orthoclase,  245,  253. 

Osmelite  (Pectolite?),  265. 

Osinium-Iridium,  117. 

Osteolite,  163. 

Ostranite,  198. 

Ottrelite,  259. 

Ouvarovite,  198. 

Owenite,  256. 

Oxalite,  187. 

Oxhaverite,  268. 

Ozarkite,  272. 

Ozokerite,  133. 

Pachnolite,  178. 

Palagonite,  257. 

Palladium,  117. 

Paper  Coal,  132. 

Paraffme,  133. 

Paragonite,  261. 

Paranthine,  240. 

Pargasite,  233. 

Parisite,  179. 

Passauite,  241. 

Patrinite  (Aikinite),  107. 

Paulite  (v.  Hypersthene),  232. 

Pearl  Mica,  215. 

Pearl  Spar  (Dolomite). 

Peaiistone,  247. 

Pectolite,  265. 

Peganite,  167. 

Pegmatolite,  245. 

Pelicanite,  219. 

Pelokonite,  189. 

Pennine,  214. 

Percy  lite,  176. 


288 


INDEX. 


Periclase,  190. 

Pericline,  246,  255. 

Peridot,  204. 

Peristerite,  246. 

Perowskite,  126. 

Perthite,  245. 

Petalite,  235. 

Petroleum,  132. 

Petzite,  113. 

Phacolite,  268,  278, 

Phsestine  (Altered  Bronzite). 

Pharmacolite,  146,  148. 

Pharmacosiderite,  145,  148. 

Phenakite,  200. 

Phengite  (Muscovite). 

PhiUipsite,  270,  276. 

Phlogopite,  213,  224. 

Phoenicite,  182. 

Pholerite,  219. 

Phosgenite,  135,  176. 

Phosphocerite,  164. 

Phosphorchalcite,  167,  170. 

Phosphorite,  163 

Phyllite  (Ottrelite  ?),  259. 

Physalite,  197. 

Piauzite,  132. 

Pickeringite,  154. 

Picotite  (Chroiniferous  Spinel). 

Picrolite,  221. 

Picrophyll,  215. 

Picrosmine,  221. 

Piedmontite,  231. 

Pilinite  (asbestifonnampliibole?) 

Pimelite,  217. 

Pinguite,  218. 

Pinite,  220. 

Pinite  group,  226. 

Pisanite,  157. 

Pissophane,  158. 

Pistacite,  231. 

Pistoniesite,  136. 

Pitchblende,  127,  190. 

Pitchstone,  247. 

Pittizite,  146. 

Plagionite,  111. 

Planerite,  167. 

Plasma  (Green  Calcedony). 

Platinum,  117. 

Platinum-Iridium,  117. 

Platinum-Iron,  117. 

Plattnerite,  122. 

Pleonaste,  197. 

Plmian,  103. 

Plumbago,  117. 

Plumbo-Calcite,  135. 

Plumosite  (Jamesonite). 

Poliauite,  119. 

PoUux,  203. 


Polyadelphite  (var.  Garnet). 
Polyargyrite,  110. 
Polybasite,  104,  110,  121,  143. 
Poly  erase,  126. 
Poly  dy  mite,  105. 
Polyhalite,  156,  161. 
Polymignite,  126. 
Polyxene  (N.  Platinum). 
Poonahlite,  272. 
Porcelain  Earth  (Kaolin),  219. 
Prase,  208. 
Prascolite,  220, 
Prasiiie  (Ehlite),  166. 
Pregrattite,  261. 
Prehnite,  267. 
Prochlorite,  214. 
Prosopite,  179. 
Proustite,  121,  123,  143.  147. 
Przibramite,  129. 
Pseudomalachite  (Phosphor- 
chalcite), 167. 

Pseudophite  (Compact  Chlorite). 
Psilomelane,  119,  125,  193. 
Psittacinite,   184. 
Pucherite,  182. 

Purple  Copper  Pyrites,  105,  108. 
Puschkinite  (Epidote). 
Pycnite,  197. 
Pycnotrope,  263. 
Pyrallolite,  222. 
Pyrargillite,  220. 
Pyrargyrite,  110,  112,  121,  123. 
Pyreneite  (Black  Garnet). 
Pyrgom,  232. 
Pyrites  : 

Arsenical  Pyrites. 

Capillary  Pyrites  (Millerite), 
105. 

Cockscomb  Pyrites,  108. 

Copper  Pyrites,  105. 

Iron  Pyrites,  105,  108. 

Magnetic  Pyrites,  105,  108. 

Purple  Copper  Pyrites,  105. 

Radiated  Pyrites  (Marca- 
site),  105. 

Spear  Pyrites,  108. 

White  Iron  Pyrites  (Mar- 

casite),  105,  108. 
Pyrochlore,  126. 
Pyrochroite,  189,  191. 
Pyrolusite,  119,  120,   125,  193, 
Pyromorphite,  163,  169. 
Pyrope,  231. 
Pyrophyllite,  214. 
Pyrophysalite  (Pycnite),  197. 
Pyropissite,  132. 
Pyrosclerite,  264. 
Pyrosmalite,  257. 


INDEX. 


289 


Pyrostibite,  149. 
Pyrostilpnite,  149. 
Pyroxene,  232,  243,  250. 
Pyrrhite  (Pyrochlor  ?). 
Pyrrhosiderite  (Gcethite),  187. 
Pyrrhotine,  105,  108, 

Quartz,  202,  208. 
Quicksilver,  115, 

Rabdionite,  189. 

Radiated  Pyrites  (Marcasite), 

105. 

Radiolite,  266. 
Rammelsbergite,  101. 
Randanite,  202. 
Raphilite  (var.  Amphibole). 
Ratofkite,  178. 
Realgar,  130,  131. 
Red  Antimony  Ore,  121,  123, 

149. 

Red  Copper  Ore,  116,  189. 
Red  Hematite,  186,  192. 
Red  Iron  Ore,  186,  192. 
Red  Lead,  187. 
Red  Ochre,  186,  192. 
Red  Silver  Ores,  121,  123,  147. 
Red  Zinc  Ore  (Zincite),  188,  193. 
Reddle,  192. 
Redruthrite  (Copper  Glance), 

106. 

Remingtonite,  139. 
Rensselaerite  (Pseudomorphous 

Steatite). 
Retinalite,  221. 
Retinite,  132. 
Reussin,  154. 
Rhcetizite  (Kyanite),  197. 
Rhagite,  145. 
Rhodizite,  171. 
Rhodochrosite.  137,  141. 
Rhodonite,  233. 
Richmondite,  167. 
Rionite,  112. 
Ripidolite,  214. 

Rittingerite,  102, 104,  121,  143. 
Rivotite,  150. 
Rock  Crystal,  202,  208. 
Rock  Salt,  174,  177. 
Romerite,  157. 
Ropperite,  137. 
Rottistite,  217. 
Romanzovite  (var.  Garnet). 
Romeite,  150. 
Roscoelite,  213. 
Rose  Quartz,  208. 
Roselite,  145. 
RubeUane,  261. 
20 


Rubellite,  199. 

Ruby,  196,  207.    ' 

Ruby  Blende  (Red  Silver  Ores), 

147. 
Ruby  Copper  (Red  Copper  Ore), 

189. 
Ruby  Silver  (Red  Silver  Ores), 

121,  123,  147. 
Rutile,  127,  129,  198,  206. 
Ryacolite,  245. 

Sagenite  (var.  Rutile). 
Sahlite,  232,  243. 
Salammoniac,  174. 
Salamstone  (var.  Corundum). 
Salmiac,  174. 
Saltpetre,  181. 
Salt,  174. 

Samarskite,  126,  196. 
Sanidine,  245. 
Sapphire,  196,  297. 
Sapphirine,  197. 
Sarcolite,  239. 
Sardianite,  151, 
Sartorite,  104. 
Sassoline,  171. 
Saynite,  105. 
Scapolite,  240,  252. 
Scheelite,  183,  185. 
Scheererite,  133. 
Schiller-spar,  215. 
Schorl,  231,  248. 
Schorlomite. 
Schroetterite,  262. 
Schreibersite  (Meteoric  Iron 

Phosphide). 

Schwartzembergite,  176. 
Scleroelase,  104. 
Scoleeite,  272,  277. 
Scorodite,  146. 
Scoulerite,  272. 
Seebachite,  268. 
Seladonite,  258. 
Selenite,  155,  161. 
Sellaite,  178. 
Senarmontite,  159. 
Sepiolite,  221. 
Serbian,  218. 
Sericite,  261. 
Serpentine,  221,  225. 
Serpentine  Group,  225. 
Seybertite  (Clintonite)  219. 
Siderite,  136,  140, 
Sideromelane,  228. 
Sideroplesite,  136. 
Sideroschisolite  (Cronstedtite), 

256. 
Sieburgite,  132. 


29: 


INDEX. 


Xanthite,  245. 
Xanthacone,  143. 
Xanthophyllite,  216. 
Xanthosiderite  (var.  Brown 

Iron  Ore). 
Xenolite,  200. 
Xenotime,  164. 
Xylite,  260. 
Xylotile,  258. 

Yellow-Ochre,  187. 
Yttrocerite,  179. 
Yttrotantalite,  127. 
Yttrotitanite,  230. 

Zalpaite,  107. 
Zaratite,  139. 


Zeagonite,  271. 

Zeolites,  273  to  278. 

.Zepharovichite,  167. 

Zeunerite,  144. 

Ziegenite,  105. 

Zinc  Blende,  108,  109,  124,  129, 

151,  159. 
Zinc  Bloom,  139. 
Zincite,  188,  193. 
Zinc  Spar,  137. 
Zinc  Vitriol  (Goslarite),  155. 
Ziukenite,  111. 
Zippeite,  157. 
Zircon,  198,  207. 
Zoisite,  244,  249. 
Zorgite,  106. 
Zwieselite,  164. 
Zygadite,  246. 


COPP,  CLARK  <fc  CO.,  PRINTERS,  C  >LBORNE  STREET,  TORONTO. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


DEC    8   1S47 


\ft! 


1  0  1954 


'  01954  (JJ 


LIBRARY  US 

AUG  2  1  1 
LIBRARY  US 

AUG  101' 
pjjGlO^U 


LD  21-100m-9,'47(A5702sl6)476 


